Endoscope device

ABSTRACT

An endoscope device obtains tissue information of a desired depth near the tissue surface. A xenon lamp ( 11 ) in a light source ( 4 ) emits illumination light. A diaphragm ( 13 ) controls a quantity of the light that reaches a rotating filter. The rotating filter has an outer sector with a first filter set, and an inner sector with a second filter set. The first filter set outputs frame sequence light having overlapping spectral properties suitable for color reproduction, while the second filter set outputs narrow-band frame sequence light having discrete spectral properties enabling extraction of desired deep tissue information. A condenser lens ( 16 ) collects the frame sequence light coming through the rotating filter onto the incident face of a light guide ( 15 ). The diaphragm controls the amount of the light reaching the filter depending on which filter set is selected.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of (1) U.S.application Ser. No. 10/333,155 filed on Jan. 16, 2003, which claimspriority based on (2) Japanese Patent Application No. 2000-221312applied in Japan on Jul. 21, 2000, (3) Japanese Patent Application No.2000-227237 applied in Japan on Jul. 27, 2000, (4) Japanese PatentApplication No. 2000-227238 applied in Japan on Jul. 27, 2000, and (5)Japanese Patent Application No. 2001-88256 applied in Japan on Mar. 26,2001 claiming priority based on the aforementioned Japanese PatentApplication No. 2000-221312 applied in Japan on Jul. 21, 2000, and thecontents disclosed in the aforementioned (1) through (5) have beenreferenced to in the present specification, Claims, and drawings and areincorporated herein by reference.

TECHNICAL FIELD

The present invention relates to an endoscope device which capturesimages of living body tissue and performs signal processing thereon.

BACKGROUND ART

Conventionally, endoscope devices for irradiating illumination light andobtaining endoscopic images within body cavities have been widely used.With such endoscope devices, an electronic endoscope has image-pickupmeans for introducing an illumination light from a light source deviceinto the body cavity using a light guide or the like and captures animage of the subject with the return light, and image-pickup signalsfrom the image-pickup means are subjected to signal processing with avideo processor, thereby displaying an endoscopic image on anobservation monitor, so that an observation portion such as an affectedarea or the like is observed.

In the event of performing normal living body tissue observation with anendoscope device, white light of the visible light region is emittedwith a light source device, frame sequence light is irradiated on thesubject via, for example, a rotating filter such as RGB or the like, andthe return light from this frame sequence light is synchronized with avideo processor, so as to obtain a color image, or a color chip isdisposed at the front face of the image-pickup surface of theimage-pickup means of the endoscope and an image is captured by dividingthe return light from white light into RGB, and image processing isperformed at the video processor, thereby obtaining a color image.

On the other hand, the absorption properties and scattering propertiesof the light at the living body tissue differ according to thewavelength of the irradiated light, so in recent years, various types ofinfrared light endoscope devices, which are capable of observing thetissues at the deep part of the living body tissue by irradiatinginfrared light on the living body tissue as the illumination light, forexample, are proposed.

However, with living body tissue diagnosis, while the deep tissueinformation near the surface of the tissue is also an important objectof observation, with the above-described infrared light endoscopedevices, only the deep tissue information deeper than the tissue surfacecan be obtained.

Also, in the event of irradiating white light on the living body tissueas RGB frame sequential light from a rotating filter, the wavelengthregions thereof differ, so while image-pickup signals from light of eachcolor has different deep part tissue information near the tissue surfaceof the living body tissue, but generally, the white light is separatedinto an RGB light with each of the wavelength regions overlapping, inorder to obtain a more natural color image for the endoscopic image bythe RGB frame sequential light.

That is, with overlapped RGB light, there is a problem that desired deeptissue information near the surface of the tissue of the living bodytissue cannot be readily recognized, since a broad range of the deeptissue information is taken into the image-pickup signals of the lightof each wavelength region.

The present invention has been made in the light of the above-describedsituation, and first, it is an object thereof to provide an endoscopedevice and light source device capable of obtaining tissue informationof a desired depth near the tissue surface of the living body tissue.

Also, it is a second object of the present invention to provide anendoscope device whereby tissue information of a desired depth near thetissue surface of the living body tissue can be separated and visuallyrecognized.

DISCLOSURE OF INVENTION

The endoscope device according to the present invention comprisesillumination light supplying means for supplying illumination lightincluding visible light region; an endoscope having image-pickup meansfor irradiating the illumination light on a subject and capturing animage of the subject by return light; and signal processing means forsignal processing of image-pickup signals from the image-pickup means;wherein band restricting means, for restricting at least one of theplurality of wavelength regions of the illumination light and performingimage formation of a band image of a discrete spectral distribution ofthe subject on the image-pickup means, are provided on the optical pathfrom the illumination light supplying means to the image-pickup means.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration diagram illustrating the configuration of anendoscope device according to a first embodiment of the presentinvention.

FIG. 2 is a configuration diagram illustrating the configuration of arotating filter shown in FIG. 1.

FIG. 3 is a diagram illustrating the spectral properties of a firstfilter set of the rotating filter shown in FIG. 2.

FIG. 4 is a diagram illustrating the spectral properties of a secondfilter set of the rotating filter shown in FIG. 2.

FIG. 5 is a diagram illustrating the structure of the living body tissuein the layer direction to be observed with the endoscope device shown inFIG. 1.

FIG. 6 is a diagram describing the state of the illumination light fromthe endoscope device shown in FIG. 1 reaching the living body tissue inthe layer direction.

FIGS. 7 a-c are diagrams illustrating each of the band images from framesequence light transmitted through the first filter set shown in FIG. 3.

FIGS. 8 a-c are diagrams illustrating each of the band images from framesequence light transmitted through the second filter set shown in FIG.4.

FIG. 9 is a diagram describing light adjustment control performed by alight adjusting circuit shown in FIG. 1.

FIG. 10 is a diagram illustrating the spectral properties of a firstmodification made on the second filter set of the rotating filter shownin FIG. 2.

FIG. 11 is a diagram illustrating the spectral properties of a secondmodification made on the second filter set of the rotating filter shownin FIG. 2.

FIG. 12 is a diagram illustrating the spectral properties of a thirdmodification made on the second filter set of the rotating filter shownin FIG. 2.

FIG. 13 is a diagram illustrating the spectral properties of a fourthmodification made on the second filter set of the rotating filter shownin FIG. 2.

FIG. 14 is a diagram illustrating a first example of spectraldistribution of a xenon lamp shown in FIG. 1.

FIG. 15 is a diagram illustrating the spectral properties of a fourthmodification made on the second filter set of the rotating filter in theevent that the spectral distribution of the xenon lamp shown in FIG. 14is applied.

FIG. 16 is a diagram illustrating spectral properties of living bodytissue illumination light with the fourth modification made on thesecond filter set of the rotating filter shown in FIG. 2.

FIG. 17 is a diagram illustrating a second example of spectraldistribution of the xenon lamp shown in FIG. 1.

FIG. 18 is a diagram illustrating an example of spectral sensitivityproperties of the CCD shown in FIG. 1.

FIG. 19 is a diagram illustrating the spectral properties of a lightreduction filter to be applied by vapor deposition to a fifthmodification made on the second filter set of the rotating filter in theevent that the spectral distribution of the xenon lamp is that in thesecond example and the spectral sensitivity properties of the CCD arethose shown in FIG. 18.

FIG. 20 is a diagram illustrating the spectral properties of the fifthmodification made on the second filter set to which the light reductionfilter shown in FIG. 19 has been applied by vapor deposition.

FIG. 21 is a configuration diagram illustrating a first modification ofthe light source device shown in FIG. 1.

FIG. 22 is a configuration diagram illustrating the configuration of thelight reduction rotating filter shown in FIG. 21.

FIG. 23 is a configuration diagram illustrating the configuration of asecond modification made on the light source device shown in FIG. 1.

FIG. 24 is a diagram illustrating the light reduction properties of afirst light reduction filter making up the light reduction filter shownin FIG. 23.

FIG. 25 is a diagram illustrating the light reduction properties of asecond light reduction filter making up the light reduction filter shownin FIG. 23.

FIG. 26 is a diagram illustrating the light reduction properties of thelight reduction filter shown in FIG. 23.

FIG. 27 is a diagram illustrating an example illustrating detailedspectral properties of the second filter set of the rotating filtershown in FIG. 2.

FIG. 28 is a diagram illustrating the spectral properties of a sixthmodification made on the second filter set of the rotating filter shownin FIG. 2.

FIG. 29 is a diagram illustrating the configuration of the principalcomponents of a modification made on the video processor shown in FIG.1.

FIG. 30 is a first diagram describing the operation of the videoprocessor shown in FIG. 29.

FIG. 31 is a second diagram describing the operation of the videoprocessor shown in FIG. 29.

FIG. 32 is a diagram illustrating the spectral properties of a seventhmodification made on the second filter set of the rotating filter shownin FIG. 2.

FIG. 33 is a diagram illustrating the spectral properties of the seventhmodification made on the second filter set shown in FIG. 32.

FIG. 34 is a configuration diagram illustrating the configuration of anendoscope device according to a second embodiment of the presentinvention.

FIG. 35 is a configuration diagram illustrating the configuration of therotating filter shown in FIG. 34.

FIG. 36 is a diagram illustrating the spectral properties of the colorchip shown in FIG. 34.

FIG. 37 is a configuration diagram illustrating the configuration of anendoscope device according to a third embodiment of the presentinvention.

FIG. 38 is a diagram illustrating the band-pass properties of the bandrestricting filter shown in FIG. 37.

FIG. 39 is a diagram illustrating the spectral properties of discretenarrow-band frame sequence light obtained by the band restricting filtershown in FIG. 38.

FIG. 40 is a diagram illustrating the band-pass properties of a firstmodification made on the band restricting filter shown in FIG. 37.

FIG. 41 is a diagram illustrating the spectral properties of discretenarrow-band frame sequence light from the band restricting filter shownin FIG. 40.

FIG. 42 is a diagram illustrating the band-pass properties of a secondmodification made on the band restricting filter shown in FIG. 37.

FIG. 43 is a diagram illustrating an example of spectral properties ofthe xenon lamp shown in FIG. 37.

FIG. 44 is a diagram illustrating the band-pass properties of a thirdmodification made on the band restricting filter shown in FIG. 37, inthe event that the spectral properties of the xenon lamp are those shownin FIG. 43.

FIG. 45 is a configuration diagram illustrating the configuration of amodification made on the light source device shown in FIG. 37.

FIG. 46 is a diagram illustrating the configuration of the lightreduction rotating filter shown in FIG. 45.

FIG. 47 is a configuration diagram illustrating the configuration of anendoscope device according to a fourth embodiment of the presentinvention.

FIG. 48 is a diagram illustrating an example of spectral distribution oflight irradiated from the light source device shown in FIG. 47 at thetime of normal observation.

FIGS. 49 a-d are diagrams illustrating the illumination timing of eachband by the electric power supply unit shown in FIG. 47, and the lightquantity control timing at that time.

FIG. 50 is a diagram illustrating an example of the spectraldistribution of light irradiated from the light source device by theelectric power supply unit shown in FIG. 47, at the time of narrow-bandobservation.

FIG. 51 is a configuration diagram illustrating the configuration of anendoscope device according to a fifth embodiment of the presentinvention.

FIG. 52 is a configuration diagram illustrating the configuration of anendoscope device according to a sixth embodiment of the presentinvention.

FIG. 53 is a configuration diagram illustrating the configuration of anendoscope device according to a seventh embodiment of the presentinvention.

FIG. 54 is a configuration diagram illustrating the configuration of thelight mixing unit shown in FIG. 53.

FIG. 55 is a diagram illustrating an example of spectral distribution ofthe xenon lamp shown in FIG. 53.

FIG. 56 is a diagram illustrating an example of spectral distribution ofthe extra-high pressure mercury lamp shown in FIG. 53.

FIG. 57 is a diagram illustrating an example of spectral distribution oflight irradiated from the light source device at the time of narrow-bandobservation performed by the light mixing unit shown in FIG. 54.

FIG. 58 is a configuration diagram illustrating the configuration of anendoscope device according to an eighth embodiment of the presentinvention.

FIG. 59 is a configuration diagram illustrating the configuration of anendoscope device according to a ninth embodiment of the presentinvention.

FIG. 60 is a diagram illustrating an adapter having a band restrictingfilter which is mountable in the tip of the electronic endoscope shownin FIG. 59.

FIG. 61 is a configuration diagram illustrating the configuration of anendoscope device according to a tenth embodiment of the presentinvention.

FIG. 62 is a configuration diagram illustrating the configuration of therotating filter shown in FIG. 61.

FIG. 63 is a diagram illustrating the spectral properties of a firstfilter set of the rotating filter shown in FIG. 62.

FIG. 64 is a diagram illustrating the spectral properties of a secondfilter set of the rotating filter shown in FIG. 62.

FIG. 65 is a diagram illustrating the structure of the living bodytissue to be observed with the endoscope device shown in FIG. 61, in thelayer direction.

FIG. 66 is a diagram describing the state of the illumination light fromthe endoscope device shown in FIG. 61 reaching the living body tissue inthe layer direction.

FIGS. 67 a-c are diagrams illustrating each of the band images fromframe sequence light transmitted through the first filter set shown inFIG. 63.

FIGS. 68 a-c are diagrams illustrating each of the band images fromframe sequence light transmitted through the second filter set shown inFIG. 64.

FIG. 69 is a diagram describing light adjustment control by a lightadjusting circuit shown in FIG. 61.

FIG. 70 is a configuration diagram illustrating the configuration of theimage processing circuit shown in FIG. 61.

FIG. 71 is a diagram illustrating a color image of a narrow-band RGBimage obtained by the image processing circuit shown in FIG. 70.

FIG. 72 is a diagram describing the creation of a matrix such that anaverage color tone is maintained in the 3×3 matrix circuit shown in FIG.70.

FIG. 73 is a diagram illustrating an example of settings of the LUTshown in FIG. 70.

FIG. 74 is a configuration diagram illustrating the configuration of amodification made to the color conversion processing circuit shown inFIG. 70.

FIG. 75 is a configuration diagram illustrating the configuration of anendoscope device according to an eleventh embodiment of the presentinvention.

FIG. 76 is a configuration diagram illustrating the configuration of theimage processing circuit shown in FIG. 75.

FIG. 77 is a configuration diagram illustrating the configuration of thecolor adjusting circuit shown in FIG. 75.

FIG. 78 is a diagram illustrating the concept of hue and saturation on aL*a*b* color space in the color adjusting circuit shown in FIG. 75.

FIG. 79 is a configuration diagram illustrating the configuration of anendoscope device according to a twelfth embodiment of the presentinvention.

FIG. 80 is a configuration diagram illustrating the configuration of therotating filter shown in FIG. 79.

FIG. 81 is a diagram illustrating the spectral transmission propertiesof the filters G2, B2 a, and B2 b, of the rotating filter shown in FIG.80.

FIG. 82 is a configuration diagram illustrating the configuration of theband selecting circuit shown in FIG. 79.

FIG. 83 is a configuration diagram illustrating the configuration of amodification made on the rotating filter shown in FIG. 79.

FIG. 84 is a diagram illustrating spectral transmission properties ofthe rotating filter shown in FIG. 83.

FIG. 85 is a configuration diagram illustrating the configuration of anendoscope device according to a thirteenth embodiment of the presentinvention.

FIG. 86 is a configuration diagram illustrating the configuration of therotating filter shown in FIG. 85.

FIG. 87 is a diagram illustrating the spectral properties of the firstfilter set of the rotating filter shown in FIG. 86.

FIG. 88 is a diagram illustrating the spectral properties of the secondfilter set of the rotating filter shown in FIG. 86.

FIG. 89 is a diagram illustrating the structure of the living bodytissue in the layer direction to be observed with the endoscope deviceshown in FIG. 85.

FIG. 90 is a diagram describing the state of the illumination light fromthe endoscope device shown in FIG. 85 reaching the living body tissue inthe layer direction.

FIGS. 91 a-c are diagrams illustrating each of the band images fromframe sequence light transmitted through the first filter set shown inFIG. 87.

FIGS. 92 a-c are diagrams illustrating each of the band images fromframe sequence light transmitted through the second filter set shown inFIG. 88.

FIG. 93 is a diagram describing light adjustment control performed by alight adjusting circuit shown in FIG. 85.

FIG. 94 is a configuration diagram illustrating the configuration of theimage processing circuit shown in FIG. 85.

FIG. 95 is a configuration diagram illustrating the configuration of anendoscope device according to a fourteenth embodiment of the presentinvention.

FIG. 96 is a configuration diagram illustrating the configuration of theimage processing circuit shown in FIG. 95.

FIG. 97 is a configuration diagram illustrating the configuration of thefiltering execution unit shown in FIG. 96.

FIG. 98 is a diagram illustrating the filter frequency properties of thefiltering execution unit shown in FIG. 97.

FIG. 99 is a diagram illustrating RGB images captured when thenarrow-band observation mode in FIG. 95.

FIG. 100 is a configuration diagram illustrating the configuration of animage processing circuit according to a fifteenth embodiment of thepresent invention.

FIG. 101 is a diagram illustrating a tone correction table in thepre-processing unit in FIG. 100.

FIG. 102 is a diagram illustrating histogram distribution applied toedge extraction processing performed by the edge extraction processingunit shown in FIG. 100.

FIG. 103 is a diagram describing processing performed by the patternextraction unit shown in FIG. 100.

BEST MODE FOR CARRYING OUT THE INVENTION

The following is a description of the embodiments of the presentinvention with reference to the drawings.

First, a first embodiment of the present invention will be describedwith reference to FIG. 1 through FIG. 33. Here, FIG. 1 is aconfiguration diagram illustrating the configuration of an endoscopedevice, FIG. 2 is a configuration diagram illustrating the configurationof a rotating filter shown in FIG. 1, FIG. 3 is a diagram illustratingthe spectral properties of a first filter set of the rotating filtershown in FIG. 2, FIG. 4 is a diagram illustrating the spectralproperties of a second filter set of the rotating filter shown in FIG.2, FIG. 5 is a diagram illustrating the structure of the living bodytissue in the layer direction to be observed with the endoscope deviceshown in FIG. 1, FIG. 6 is a diagram describing the state of theillumination light from the endoscope device shown in FIG. 1 reachingthe living body tissue in the layer direction, FIG. 7 is a diagramillustrating each of the band images from frame sequence lighttransmitted through the first filter set shown in FIG. 3, FIG. 8 is adiagram illustrating each of the band images from frame sequence lighttransmitted through the second filter set shown in FIG. 4, FIG. 9 is adiagram describing light adjustment control performed by a lightadjusting circuit shown in FIG. 1, FIG. 10 is a diagram illustrating thespectral properties of a first modification made on the second filterset of the rotating filter shown in FIG. 2, FIG. 11 is a diagramillustrating the spectral properties of a second modification made onthe second filter set of the rotating filter shown in FIG. 2, FIG. 12 isa diagram illustrating the spectral properties of a third modificationmade on the second filter set of the rotating filter shown in FIG. 2,FIG. 13 is a diagram describing the operations of a third modificationmade on the second filter set of the rotating filter shown in FIG. 2,FIG. 14 is a diagram illustrating a first example of spectraldistribution of a xenon lamp shown in FIG. 1, FIG. 15 is a diagramillustrating the spectral properties of a fourth modification made onthe second filter set of the rotating filter in the event that thespectral distribution of the xenon lamp shown in FIG. 14 is applied,FIG. 16 is a diagram illustrating spectral properties of living bodytissue illumination light with the fourth modification made on thesecond filter set shown in FIG. 14, FIG. 17 is a diagram illustrating asecond example of spectral distribution of the xenon lamp shown in FIG.1, FIG. 18 is a diagram illustrating an example of spectral sensitivityproperties of the CCD shown in FIG. 1, FIG. 19 is a diagram illustratingthe spectral properties of a light reduction filter to be applied byvapor deposition to a fifth modification made on the second filter setof the rotating filter in the event that the spectral distribution ofthe xenon lamp is that in the second example and the spectralsensitivity properties of the CCD are those shown in FIG. 18, FIG. 20 isa diagram illustrating the spectral properties of the fifth modificationmade on the second filter set to which the light reduction filter shownin FIG. 19 has been applied by vapor deposition, FIG. 21 is aconfiguration diagram illustrating a first modification of the lightsource device shown in FIG. 1, FIG. 22 is a configuration diagramillustrating the configuration of the light reduction rotating filtershown in FIG. 21, FIG. 23 is a configuration diagram illustrating theconfiguration of a second modification made on the light source deviceshown in FIG. 1, FIG. 24 is a diagram illustrating the light reductionproperties of a first light reduction filter making up the lightreduction filter shown in FIG. 23, FIG. 25 is a diagram illustrating thelight reduction properties of a second light reduction filter making upthe light reduction filter shown in FIG. 23, FIG. 26 is a diagramillustrating the light reduction properties of the light reductionfilter shown in FIG. 23, FIG. 27 is a diagram illustrating an exampleillustrating detailed spectral properties of the second filter set ofthe rotating filter shown in FIG. 2, FIG. 28 is a diagram illustratingthe spectral properties of a sixth modification made on the secondfilter set of the rotating filter shown in FIG. 2, FIG. 29 is a diagramillustrating the configuration of the principal components of amodification made on the video processor shown in FIG. 1, FIG. 30 is afirst diagram describing the operations of the video processor shown inFIG. 29, FIG. 31 is a second diagram describing the operations of thevideo processor shown in FIG. 29, FIG. 32 is a diagram illustrating thespectral properties of a seventh modification made on the second filterset of the rotating filter shown in FIG. 2, and FIG. 33 is a diagramillustrating the spectral properties of the seventh modification made onthe second filter set shown in FIG. 32.

As shown in FIG. 1, the endoscope device 1 according to the presentembodiment is configured of an electronic endoscope 3 which is insertedinside the body cavity and which has a CCD 2 serving as image-pickupmeans for capturing images of tissue within the body cavity, a lightsource device 4 for supplying illumination light to the electronicendoscope 3, and a video processor 7 for subjecting image-pickup signalsfrom the CCD 2 of the electronic endoscope 3 to signal processing anddisplaying endoscopic images on an observation monitor 5 or encoding theendoscopic images and outputting to an image filing device 6 ascompressed images.

The light source device 4 is configured of a xenon lamp 11 for emittingillumination light, a heat ray cut filter 12 for shielding heat raysfrom the white light, a diaphragm device 13 for controlling the lightquantity of the white light through the heat ray cut filter 12, arotating filter 14 for turning the illumination light into framesequence light, a condenser lens 16 for collecting the frame sequencelight coming through the rotating filter 14 onto the incident face of alight guide 15 disposed within the electronic endoscope 3, and a controlcircuit 17 for controlling the rotation of the rotating filter 14.

As shown in FIG. 2, the rotating filter 14 is formed in a disk-likeshape and has a double structure with the center as the rotating axis,wherein an R1 filter 14 r 1, a G1 filter 14 g 1, and a B1 filter 14 b 1making up a first filter set for outputting frame sequence light havingoverlapping spectral properties suitable for color reproduction such asindicated in FIG. 3 are situated on the outer sector, and wherein an R2filter 14 r 2, a G2 filter 14 g 2, and a B2 filter 14 b 2 making up asecond filter set for outputting narrow-band frame sequence light havingdiscrete spectral properties enabling extraction of desired deep tissueinformation such as indicated in FIG. 4 are situated on the innersector. As shown in FIG. 1, the rotating filter 14 is rotated by thecontrol circuit 17 performing driving control of a rotating filter motor18, and movement in the radial direction (movement which isperpendicular to the optical path of the rotating filter 14, which isselectively moving the first filter set or second filter set of therotating filter 14 onto the optical path) is performed by a modeswitch-over motor 19 based on control signals from a mode switch-overcircuit 42 within the later-described video processor 7.

Note that electric power is supplied to the xenon lamp 11, diaphragmdevice 13, rotating filter motor 18, and mode switch-over motor 19, fromthe electric power supply unit 10.

Returning to FIG. 1, the video processor 7 is configured comprising aCCD driving circuit 20 for driving the CCD 2, an amplifier 22 foramplifying image-pickup signals wherein images are captured in the bodycavity tissue by the CCD 2 through an objective optical system 21, aprocess circuit 23 for performing correlated double sampling and noisereduction and so forth, with regard to image-pickup signals comingthrough the amplifier 22, an A/D converter 24 for converting theimage-pickup signals passing through the process circuit 23 into imagedata of digital signals, a white balance circuit 25 for subjecting theimage data from the A/D converter 24 to white balance processing, aselector 26 and synchronizing memories 27, 28, and 29, for synchronizingthe frame sequence light from the rotating filter 14, an imageprocessing circuit 30 for reading out each set of image data of theframe sequence light stored in the synchronizing memories 27, 28, 29,and subjecting these to gamma correction processing, outline enhancementprocessing, color processing, etc., D/A circuits 31, 32, and 33, forconverting the image data from the image processing circuit 30 intoanalog signals, an encoding circuit 34 encoding the output of the D/Acircuits 31, 32, and 33, and a timing generator 35 for inputtingsynchronizing signals synchronized with the rotation of the rotatingfilter 14 from the control circuit 17 of the light source device 4, andoutputting various types of timing signals to the above-describedcircuits.

Also, a mode switch-over switch 41 is provided in the electronicendoscope 2, with the output of this switch-over switch 41 being outputto the mode switch-over circuit 42 within the video processor 7. Themode switch-over circuit 42 of the video processor 7 makes output ofcontrol signals to a light adjusting circuit 43, a light adjustmentcontrol parameter switch-over circuit 44, and the mode switch-over motor19 of the light source 4. The light adjustment control parameterswitch-over circuit 44 outputs light adjustment control parameterscorresponding to the first filter set or second filter set of therotating filter 14 to the light adjusting circuit 43, and the lightadjusting circuit 43 controls the diaphragm device 13 of the lightsource device 4 based on the control signals from the mode switch-overcircuit 42 and light adjusting parameters from the light adjustmentcontrol parameter switch-over circuit 44, so as to perform appropriatebrightness control.

Next, the operations of the endoscope device according to the presentembodiment configured thus will be described.

As shown in FIG. 5, a body cavity tissue 51 often has a structurewherein there is a distribution of different absorbent material such asblood vessels in the depth direction, for example. There is primarily agreater distribution of capillaries 52 near the surface of mucusmembranes, blood vessels 53 which are thicker than the capillaries arealso distributed along with the capillaries at the middle layer which isdeeper than this layer, and even thicker blood vessels 54 aredistributed at even deeper layers.

On the other hand, the permeation depth of the light in the depthdirection as to the body cavity tissue 51 is dependent on the wavelengthof light, and with illumination light containing the visible region, asshown in FIG. 6, in the case of light with a short wavelength such asblue (B), the light only reaches around the surface layer due to theabsorption properties and scattering properties at the living bodytissue, being subjected to absorption and scattering within the range upto that depth, so light coming out from the surface is observed. Also,in the case of green (G) light with a wavelength longer than that ofblue (B) light, the light reaches a depth deeper than the range wherethe blue (B) light reaches, is subjected to absorption and scatteringwithin the range at that depth, and light coming out from the surface isobserved. Further, red (R) light with a wavelength longer than that ofgreen (G) light, reaches a range even deeper.

At the time of performing normal observation, the mode switch-over motor19 is controlled by the mode switch-over circuit within the videoprocessor 7 with control signals, so that the R1 filter 14 r 1, G1filter 14 g 1, and B1 filter 14 b 1, making up the first filter set ofthe rotating filter 14, are positioned on the optical path of theillumination light.

With the R1 filter 14 r 1, G1 filter 14 g 1, and B1 filter 14 b 1, thewavelength regions are each overlapped as shown in FIG. 3, so at thetime of normal observation of the body cavity tissue 51, a band imagehaving shallow layer and middle layer tissue information containing agreat amount of tissue information at the shallow layer such shown in“a” in FIG. 7 is captured in the image-pickup signals taken by the CCD 2with the B1 filter 14 b 1, a band image having shallow layer and middlelayer tissue information containing a great amount of tissue informationat the middle layer such as shown in “b” in FIG. 7 is captured in theimage-pickup signals taken by the CCD 2 with the G1 filter 14 g 1, andfurther, a band image having middle layer and deep layer tissueinformation containing a great amount of tissue information at the deeplayer such shown in “c” in FIG. 7 is captured in the image-pickupsignals taken by the CCD 2 with the R1 filter 14 r.

These RGB image-pickup signals are synchronized with the video processor7 and subjected to signal processing, thus enabling an endoscopic imagewith desired or natural color reproduction to be obtained as anendoscopic image.

On the other hand, upon the mode switch-over switch 41 of the electronicendoscope 3 being pressed, the signals thereof are input to the modeswitch-over circuit 42 of the video processor 7. The mode switch-overcircuit 42 outputs control signals to the mode switch-over motor 19 ofthe light source device 4, thereby moving the first filter set of therotating filter 14 that was on the optical path at the time of normalobservation, and drives the rotating filter 14 with regard to theoptical path so that the second filter set is positioned upon theoptical path.

In the event of performing narrow-band light observation of the bodycavity tissue 51 with the second filter set, the R2 filter 14 r 2, G2filter 14 g 2, and B2 filter 14 b 2 make the illumination light to benarrow-band frame sequence light with discrete spectral properties asshown in FIG. 4, so a band image having tissue information at a shallowlayer such as shown in “a” in FIG. 8 is captured in the image-pickupsignals taken by the CCD 2 with the B2 filter 14 b 2, a band imagehaving tissue information at the middle layer such as shown in “b” inFIG. 8 is captured in the image-pickup signals taken by the CCD 2 withthe G2 filter 14 g 2, and a band image having tissue information at thedeep layer such as shown in “c” in FIG. 8 is captured in theimage-pickup signals taken by the CCD 2 with the R2 filter 14 r 2.

As can be clearly understood from FIG. 3 and FIG. 4, at this time, thequantity of transmitted light from the second filter set is less thanthe quantity of transmitted light from the first filter set, because thebands thereof are narrowed, so the light adjusting circuit 43 controlsthe diaphragm device 13 by outputting light adjustment controlparameters according to the first filter set or second filter set of therotating filter 14, from the light adjustment control parameterswitch-over circuit 44 to the light adjusting circuit 43, thereby, asshown in FIG. 9, controlling the diaphragm device 13 when makingnarrow-band light observation so as to control light quantity Mx with adiaphragm control curve 62 corresponding to a set value Lx, with respectto, for example, a linear diaphragm control line 61 by the diaphragmdevice 13 in normal observation, corresponding to the set value Lx on anunshown setting panel of the video processor 7.

Specifically, the aperture level value corresponding to the lightquantity setting value Lx changes from Mx1 to Mx2 as shown in FIG. 9,being interlocked with changing the first filter set to the secondfilter set, and consequently, the diaphragm is controlled in thedirection of being opened, and acts to compensate for reduction in thequantity of illumination light by the filter which narrows the band.

Thus, image data with sufficient brightness can be obtained even whenmaking narrow-band light observation.

Thus, according to the present embodiment, a transfer to narrow-bandlight observation can be made by pressing the mode switch-over switch 41as necessary so as to switch from the first filter set of the rotatingfilter 14 to the second filter set while performing normal observationof the body cavity tissue 51, and in this narrow-band light observation,each of the layers of the body cavity tissue 51 can be obtained asimage-pickup signals in the state of the living body tissue of eachbeing separated by the second filter set of the rotating filter 14, andalso image-pickup signals of a suitable light quantity can be obtainedby controlling the diaphragm device 13, so tissue information about eachof the layers of the body cavity tissue 51 which is important fordiagnosis can be visually recognized in a sure manner and can bediagnosed in a more accurate manner.

Now, while the second filter set has been made to be a filter set withillumination light spectrum properties such as shown in FIG. 4 (R2filter 14 r 2, G2 filter 14 g 2, and B2 filter 14 b 2), the invention isnot restricted to this, and as a first modification of the second filterset, the second filter may be a filter set which generates narrow-bandframe sequence light with discrete spectral properties as shown in FIG.10, for example, from the illumination light. With the filter setaccording to this first modification, the G filter and R filter are thesame as the G filter and the R filter of the first filter set, and onlythe B filter carries a narrow bandwidth. This modification isparticularly suitable for cases wherein there is interest in thecapillaries structures and the like near the surface of the living bodytissue, and conventional images suffice for the other band images.

Also, the filter properties are not restricted to visible light, and asa second modification of the second filter set, the second filter may bea filter set which generates narrow-band frame sequence light withdiscrete spectral properties as shown in FIG. 11, for example, from theillumination light. This filter set according to the second modificationis suitable for obtaining any image information not applicable withnormal observation, by setting B to the near-ultraviolet region and R tothe near-infrared region, in order to observe the irregular portions atthe surface of the organism and absorbents at extremely deep layers.

Further, as the third modification of the second filter set, the secondfilter may be a filter set comprising two filters B2 a and B2 b whichcome close at the near-wavelength region, instead of the G filter, asshown in FIG. 12. This is suitable for visualizing minute differences inscattering properties rather than absorption properties, using the factthat the wavelength bandwidth in this area only permeates to around theextreme surface layer of the organism. That is, as shown in FIG. 13,configuring the filter at a position where the scattering propertiesgreatly change such that the absorption properties of the organism areapproximately equal at the center wavelength of B2 a and B2 b issuitable for visualizing scattering properties near the surface.Medically, application can be envisioned for diagnosis for recognizingdisorders involving disarray in cell arrays near the surface of mucousmembranes, such as for early cancer or the like.

Also, generally, xenon lamps and the like are often manufactured so asto shield ultraviolet light. FIG. 14 shows an example of spectraldistribution of the illumination light source. Accordingly, with the Bregion in the second filter set, even in the event that the shortwavelength side is given open properties as a transmitting area as shownin FIG. 15, the properties are as such as shown in FIG. 16 in thecombination with a spectral properties of the light source, andconsequently, narrow-band illumination light properties can be realized.Also, manufacturing of the optical filter is normally often performed byvapor deposition of a multi-layer interference film filter, and withthat manufacturing method, the vapor deposition in with many layers offilm must be performed in order to yield narrow-band for the spectraltransmissivity properties thereof, resulting in increased costs andthicker filters, but the manufacturing costs and thickness can bereduced by using the lump properties in this way and giving openproperties to one side.

Also, in the event that the spectral distribution of the light sourceare such as shown in FIG. 17, or in the event that the spectralsensitivity properties of the CCD are as shown in FIG. 18, the lightadjustment is set somewhat brighter to compensate for the reduction inlight quantity by narrowing the bandwidth, in association with switchingover from the first filter set of the rotating filter 14 to the secondfilter set, and consequently it can be conceived that the B2 band imageis suitable, but that the G2 band image and R2 band image tend to besaturated. Or, the white balance is adjusted at the white balancecircuit 25 shown in FIG. 1, and consequently, the B2 band image with alow brightness level is excessively amplified by the second filter set,light source device, and CCD sensitivity properties, resulting in animage with poor SN being observed.

Accordingly, it is necessary to control not only the bandwidthproperties but also the peak transmittance properties as well, takinginto consideration factors which affect the system spectral sensitivity,such as light source spectral distribution properties, CCD spectralsensitivity properties, and so forth.

Accordingly, taking into consideration the system spectral sensitivityproperties other than filter, and light adjustment properties, anarrangement may be configured as the fifth modification of the secondfilter set, wherein a light reducing filter having light reducingproperties “a” and “b” as shown in FIG. 19 is vapor-deposited or adheredto the R2 filter 14 r 2 or G2 filter 14 g 2 of the rotating filter 14 toobtain an image with suitable brightness. Consequently, a narrow-bandfilter set having properties such as shown in FIG. 20, can be obtained.In this way, not only the bandwidth properties, but also thetransmissivity properties thereof can also be suitably set, so imageswith optimal brightness for each band can be observed.

As a method for controlling not only bandwidth properties but also peaktransmissivity properties, taking into consideration factors whichaffect the system spectral sensitivity, such as light source spectraldistribution properties, CCD spectral sensitivity properties, and soforth, a configuration may be made wherein, in addition to a lightreducing filter being vapor-deposited or adhered to the R2 filter 14 r 2and G2 filter 14 g 2 of the rotating filter 14 as described above, afirst modification of the light source device 4 as shown in FIG. 21 maycomprise a light reducing rotating filter 61 provided all the opticalpath, separate from the rotating filter 14. As shown in FIG. 22, thislight reducing rotating filter 61 has the same double structure as therotating filter 14 (see FIG. 2) and, with the portions corresponding tothe R1 filter 14 r 1, G1 filter 14 g 1, B1 filter 14 b 1, and B2 filter14 b 2 of the rotating filter 14 being transmitting portions, andcomprising light reducing filters 62 and 63 for reducing the light ofthe bandwidth portions corresponding only to the R2 filter 14 r 2 and G2filter 14 g 2, respectively. The light reducing rotating filter 61 isrotationally driven by a rotating filter motor 64 based on controlsignals of the control circuit 17 in the same way as the rotating filter14, and also is capable of motion perpendicular to the optical path inthe radial direction thereof by a mode switch-over motor 65 based oncontrol signals from the mode switch-over circuit 42, and the drivingtiming thereof is carried out synchronously with the rotating filter 14.

Also, as a method for controlling not only bandwidth properties but alsopeak transmissivity properties, taking into consideration factors whichaffect the system spectral sensitivity, such as light source spectraldistribution properties, CCD spectral sensitivity properties, and soforth, a second modification of the light source device 4 comprises alight reducing filter 71, instead of the light source device comprisingthe light reducing rotating filter 61 as described above. The lightreducing filter 71 has desired bandwidth transmissivity by combinationof multiple filters and is insertable to and extractable from theoptical path by a filter driving motor 72 based on control signals fromthe mode switch-over circuit 42, the driving thereof being extracted atthe time of the first filter of the rotating filter 14, and inserted atthe time of the second filter, as shown in FIG. 23. This light reducingfilter 71 is capable of controlling not only bandwidth properties butalso peak transmissivity properties, by having light reducing propertiessuch as shown in FIG. 26, by combining, for example, a first lightreducing filter having light reducing properties shown in FIG. 24 and asecond light reducing filter having light reducing properties shown inFIG. 25.

Now, as for an example of specific spectral properties of theabove-described R2 filter 14 r 2, G2 filter 14 g 2, and B2 filter 14 b2, as shown in FIG. 27, the R2 filter 14 r 2 has band-pass propertiesincluding 600 nm for the wavelength bandwidth and 20 to 40 nm for a fullwidth at half maximum, the G2 filter 14 g 2 has band-pass propertiesincluding 540 nm for the wavelength bandwidth and 20 to 40 nm for a fullwidth at half maximum, and further the B2 filter 14 b 2 has band-passproperties including 420 nm for the wavelength bandwidth and 20 to 40 nmfor a full width at half maximum.

With the spectral properties such as shown in FIG. 27, the capillarystructure on the mucous membrane surface can be reproduced in highcontrast by making the observation with an illumination light havingnarrow-band properties including 420 nm which is the band at whichabsorption of blood by visible light is great, and further, thedistribution in the depth direction of the absorbents within the bodymucous membrane can be reproduced with a different color, so therelative position of the absorbents other than the blood vessel imagesand the like in the depth direction can be conceptualized.

Also, as a modification made on the above-described R2 filter 14 r 2, G2filter 14 g 2, and B2 filter 14 b 2, the G′ filter 14 g′, G″ filter 14g″, and B2 filter 14 b 2 shown in FIG. 28 may be used, wherein the G′filter 14 g′ has band-pass properties including 550 nm for thewavelength bandwidth and 20 to 40 nm for a full width at half maximum,the G″ filter 14 g″ has band-pass properties including 500 nm for thewavelength bandwidth and 20 to 40 nm for a full width at half maximum,and further the B2 filter 14 b 2 has band-pass properties including 420nm for the wavelength bandwidth and 20 to 40 nm for a full width at halfmaximum.

With the spectral properties such as shown in FIG. 28, the capillarystructure on the mucous membrane surface can be reproduced in highcontrast by making the observation with an illumination light havingnarrow-band properties including 420 nm which is the band at whichabsorption of blood by visible light is great, and further, providingband-pass light around 500 nm which is the neighboring bandwidth canrealize image reproduction specialized for the structure of the mucousmembrane surface.

Also, the aperture level value corresponding to the light quantitysetting value Lx is changed from Mx1 to Mx2 as shown in FIG. 9, beinginterlocked with the change from the first filter set to the secondfilter set, and consequently, the diaphragm is controlled in thedirection of being opened, acting to compensate for reduction in theillumination light quantity by the filter which narrows the band, butthe exposure time may be extended to increase the irradiated lightquantity.

However, the organism which is the subject is not necessarilystationary, and does have peristalsis and pulse, so performing freezingoperations while observing the image means that the image moves whileexposing the CCD, and increases in the irradiated light quantity byextending this exposure time, and thus creates problems in that shakingof the image increases.

Accordingly, as a modification of the video processor 7, memories 180,181, and 182 for pre-freezing, for constantly recording several framesof images, are provided after the synchronizing memories 27, 28, and 29,and a motion detecting circuit 190 for detecting motion by comparingimage data between fields by the output signals of the synchronizingmemories 27, 28, and 29, and the input signals of the selector 26, isprovided, as shown in FIG. 29.

Due to such a configuration, pressing the mode switch-over switch 41provided on the electronic endoscope 3 controls the rotation of therotating filter 14 so that the mode switch-over circuit 42 controls thetiming generator 35 such that the exposure time is made to be twice thatof normal observation time by the control circuit 17 of the light sourcedevice 4 (the rotating speed for the second filter set of the rotatingfilter 14 is made to be a half of the rotating speed of the first filterset).

Also, in the event that a freeze switch 185 provided in the electronicendoscope 3 is pressed, image data is compared between fields by amotion detecting circuit 190 so as to detect motion, at the timing shownin FIG. 30 at the time of normal observation, and at the timing shown inFIG. 31 at the time of narrow-band observation, thereby controllingupdating of the image data to be recorded in the memories 180, 181, and182.

Specifically, taking a normal observation time shown in FIG. 30 as anexample for description, image data R0 of one field period stored in thesynchronizing memory 27 is compared with image data G0 input from theselector 26 by the motion detecting circuit 190 (the first comparison),and further image data G0 of one field period stored in thesynchronizing memory 28 is compared with image data B0 input from theselector 26 (the second comparison), and in the event that judgment ismade that there are no movements between either, the mode switch-overcircuit 42 controls the timing generator 35, and then in the next fieldperiod (the period denoted by an asterisk in the figure), the image dataR0, G0, and B0, stored in the synchronizing memories 27, 28, and 29, iswritten to the memories 180, 181, and 182.

Also, following judgment that there is no motion as the result of theabove second comparison by the motion detecting circuit 190, image dataB0 of one field period stored in the synchronizing memory 29 is comparedwith image data R1 input from the selector 26 (the third comparison),and in the event that judgment is made that there is no movement as theresults of the third comparison as well, the mode switch-over circuit 42controls the timing generator 35, and then in the next field period (theperiod denoted by a star in the figure), the image data R1, G0, and B0,stored in the synchronizing memories 27, 28, and 29, is overwritten onthe memories 180, 181, and 182.

Also, in the event that judgment is made there is movement as the resultof the third comparison, there is no updating in the above-describedperiod denoted by a star, and the data recorded in the above period iskept in the memories 180, 181, and 182.

Thus, updating of the memories 180, 181, and 182 is sequentiallyperformed at the subsequent field. Also, the same updating is performedfor the memories 180, 181, and 182, with narrow-band observation aswell, except that the exposure time is doubled, as shown in FIG. 31.

Upon the freeze switch 185 provided in the electronic endoscope 3 beingpressed, the mode switch-over circuit 42 controls the timing generator35 to stop the reading out from the synchronizing memories 27, 28, and29, and the image data read out from the memories 180, 181, and 182 isoutput to the image processing circuit 30.

However, in the event that there is no image data in the memories 180,181, and 182, or immediately following the mode switch-over switch 41being pressed and switching over having been made to the second filterset of the rotating filter 14, the reading out from the synchronizingmemories 27, 28, and 29, continues even if the freeze switch 185 ispressed, until motion is detected by the motion detecting circuit 190,and reading out from the synchronizing memories 27, 28, and 29, isstopped for the first time upon motion being detected.

Providing the memories 180, 181, and 182 and the motion detectingcircuit 190 as shown in FIG. 29 allows images wherein shaking issuppressed to a minimum to be obtained even in the event of freezing ina state that the exposure time has been extended for narrow-bandobservation.

Now, generally, florescent images of living body tissue from excitationlight do not reflect the fine structure of the surface of mucousmembranes, but do bring to light disorders which are not readilydiscovered with visible light. On the other hand, the fine structures ofthe surface of the mucous membranes, such as capillary structure images,and so forth, are known to be crucial information for differentialdiagnosis of disorders. Accordingly, an arrangement may be made whereinthese two types of information are combined and displayed as an image,thereby improving diagnostic capabilities.

Specifically, a second filter set of the rotating filter is configuredof an excitation light F filter 14 f, and G2 filter 14 g 2 and B2 filter14 b 2, as shown in FIG. 32, instead of the R2 filter 14 r 2, G2 filter14 g 2, and B2 filter 14 b 2. Now, the spectral properties with theexcitation light F filter 14 f are properties such as shown in FIG. 33.

Upon irradiating narrow-band excitation light from the F filter 14 fonto the living body tissue, fluorescent light with the wavelength suchas shown in FIG. 33 is emitted from the living body tissue. Accordingly,with the above-described embodiment, normal observation giving weight tocolor reproduction properties has wide band properties, and highlyfunctional observation by fluorescent light and narrow-band lightsuperimposed, can be switched between and applied.

In this way, observation of disorders which cannot be readily discoveredwith visible light by florescent light observation, and detailedobservation of the surface of mucous membranes by narrow-band light canbe performed, thereby improving diagnostic capabilities.

Next, a second embodiment of the present invention will be describedwith reference to FIG. 34 through FIG. 36.

FIG. 34 is a configuration diagram illustrating the configuration of anendoscope device, FIG. 35 is a configuration diagram illustrating theconfiguration of the rotating filter shown in FIG. 34, and FIG. 36 is adiagram illustrating the spectral properties of the color chip shown inFIG. 34.

The second embodiment is almost the same as the first embodiment, soonly the differing points will be described, and the same configurationswill be denoted with the same reference numerals and description thereofwill be omitted.

As shown in FIG. 34, with the electronic endoscope 3 according to thepresent embodiment, a color chip 81 is disposed on the front face of theCCD 2, thereby making up a color CCD 2 a, configuring an endoscopedevice 1 of a synchronous system when performing normal observation.Color image signals from the color CCD 2 a are converted into colorimage data at the A/D converter 24, subsequently subjected to colorseparation at a color separating circuit 82, then input to the whitebalance circuit 25, and stored in memories 83, 84, and 85, via theselector 26, subsequently subjected to interpolation processing or thelike at the image processing circuit 30, following which desired imageprocessing is performed.

As shown in FIG. 35, the rotating filter 86 of the light source device 4is made up of an R2 filter 14 r 2, G2 filter 14 g 2, and B2 filter 14 b2, having spectral properties which are the same as that of the secondfilter set in the first embodiment, rotationally driven by the rotatingfilter motor 18 based on control signals from the control circuit 17,and being insertable to and extractable from the optical path by afilter driving motor 87 based on control signals from the modeswitch-over circuit 42 which has received instruction signals from themode switch-over switch 41 provided in the electronic endoscope 3.

With the present embodiment thus configured, a rotating filter 86 isextracted from the optical path at normal observation time, so thatwhite light is irradiated on the living body tissue. The living bodytissue image of the white light is captured by the color CCD 2 a. Thespectral properties of the color chip 81 on the front face of the CCD 2a at this time are shown in FIG. 36.

On the other hand, when making narrow-band like observation, therotating filter 86 is inserted into the optical path, with framesequence light from the R2 filter 14 r 2, G2 filter 14 g 2, and B2filter 14 b 2, irradiated to the living body tissue. A living bodytissue image of this frame sequence light is taken by the color CCD 2 a.

Accordingly, frame sequence light having discrete narrow-band spectralproperties from the R2 filter 14 r 2, G2 filter 14 g 2, and B2 filter 14b 2, is irradiated on to the body organism at the time of narrow-bandobservation, so the same advantages as those of the first embodiment canbe obtained with the present embodiment, as well.

Next, a third embodiment of the present invention will be described withreference to FIG. 37 through FIG. 46.

FIG. 37 is a configuration diagram illustrating the configuration of anendoscope device, FIG. 38 is a diagram illustrating the band-passproperties of the band restricting filter shown in FIG. 37, FIG. 39 is adiagram illustrating the spectral properties of discrete narrow-bandframe sequence light obtained by the band restricting filter shown inFIG. 38, FIG. 40 is a diagram illustrating the band-pass properties of afirst modification made on the band restricting filter shown in FIG. 37,FIG. 41 is a diagram illustrating the spectral properties of discretenarrow-band frame sequence light from the band restricting filter shownin FIG. 40, FIG. 42 is a diagram illustrating the band-pass propertiesof a second modification made on the band restricting filter shown inFIG. 37, FIG. 43 is a diagram illustrating an example of spectralproperties of the xenon lamp shown in FIG. 37, FIG. 44 is a diagramillustrating the band-pass properties of a third modification made onthe band restricting filter shown in FIG. 37, in the event that thespectral properties of the xenon lamp are those shown in FIG. 43, FIG.45 is a configuration diagram illustrating the configuration of amodification made on the light source device shown in FIG. 37, and FIG.46 is a diagram illustrating the configuration of the light reductionrotating filter shown in FIG. 45.

The third embodiment is almost the same as the first embodiment, so onlythe differing points will be described, and the same configurations willbe denoted with the same reference numerals and description thereof willbe omitted.

As shown in FIG. 37, the light source device 4 according to the presentembodiment comprises a rotating filter 91 upon which are disposed an R1filter 14 r 1, G1 filter 14 g 1, and B1 filter 14 b 1, and a bandwidthredistricting filter 92 having multi-peak band-pass properties (R2 band,G2 band, and B2 band), as shown in FIG. 38, for restricting thebandwidth of transmitted light, where the rotating filter 91 isrotationally driven by the rotating filter motor 18 based on controlsignals from the control circuit 17, and the bandwidth restrictingfilter 92 is insertable to and extractable from the optical path by afilter driving motor 87 based on control signals from the modeswitch-over circuit 42 which has received the instruction signals fromthe mode switch-over switch 41.

With the present embodiment thus configured, the bandwidth restrictingfilter 92 is inserted into the optical path, whereby the frame sequencelight transmitting the rotating filter 91 becomes discrete narrow-bandframe sequence light as shown in FIG. 39, and this narrow-band framesequence light is irradiated on the living body tissue, so the sameadvantages as those of the first embodiment can be obtained with thepresent embodiment, as well.

Now, with the present embodiment, the bandwidth restricting filter 92 isconfigured to have narrow-band properties at the three bands of RGB asshown in FIG. 38, but the embodiment is not restricted to this, and inthe event that improvement in only the observation capabilities of thebody surface structures is desired, there is no need to make all threebands narrow bandwidth, rather, only the B band needs to be narrow, so abandwidth restricting filter having irregular multi-peak band-passproperties may be used as shown in FIG. 40, and combining such abandwidth restricting filter with the RGB rotating filter 91 allowsframe sequence light having narrow-band properties for the B band aloneto be irradiated onto the living body tissue, as shown in FIG. 41.

In order to provide the narrow-band properties for the B band alone, thebandwidth restricting filter 92 may be made to be a bandwidthrestricting filter wherein the RGB light is made to be light of B′alone, as shown in FIG. 42, with the specific example of narrow-bandproperties of this B′ alone being band-pass properties including 420 nmfor the wavelength bandwidth and 20 to 40 nm for a full width at halfmaximum.

With the spectral properties such as shown in FIG. 42, the capillarystructure on the mucous membrane surface can be reproduced in highcontrast by making the observation with an illumination light havingnarrow-band properties including 420 nm which is the band at whichabsorption of blood by visible light is great.

Also, in the event that the shielding properties of the short wavelengthregion side of the rotating filter 91 can be used, such as in caseswherein the spectral properties of the xenon lamp have properties ofattenuation in the short wavelength region, as shown in FIG. 43, abandwidth restriction filter having open properties instead of havingband-pass properties at the short wavelength side may be used, as shownin FIG. 44.

Also, taking into consideration the fact that energy for the lamp dropsin the short wavelength region, and further that the CCD spectralsensitivity properties lose sensitivity in this region, the gain of theB2 band image is excessively increased as a result of color adjustmentsprocessing such as white balance and the like, thereby yielding an imagewith a very great amount of noise.

Accordingly, as a modification of the light source device, the lightquantity for each band is adjusted at the light source side so that eachband image has appropriate SN properties even after performing whitebalance taking into consideration the spectral properties other thanthose of the filter, such as of the lamp, CCD, etc., by inserting thelight reducing rotating filter 95 into the optical path, as shown inFIG. 45.

That is, as shown in FIG. 46, each part of the light reducing rotatingfilter 95 corresponding to the B1 filter 14 b 1 of the rotating filter91 is configured as a transmitting portion, and the parts correspondingto the R1 filter 14 r 1 and the G1 filter 14 g 1 are configured as lightreducing filters for reducing the light of the corresponding bandwidths.The light reducing rotating filter 95 is rotationally driven by arotating filter motor 96 based on control signals from the controlcircuit 17 in the same way as the rotating filter 91, and also iscapable of moving perpendicularly to the optical path in the radialdirection thereof by a mode switch-over motor 97 based on controlssignals from the mode switch-over circuit 42, and the driving timingthereof is carried out synchronously with that of the rotating filter91.

Next, a fourth embodiment of the present invention will be describedwith reference to FIG. 47 to FIG. 50.

FIG. 47 is a configuration diagram illustrating the configuration of anendoscope device, FIG. 48 is a diagram illustrating an example ofspectral distribution of light irradiated from the light source deviceshown in FIG. 47 at the time of normal observation, FIG. 49 is a diagramillustrating the illumination timing of each band by the electric powersupply unit shown in FIG. 47, and the light quantity control timing atthat time, and FIG. 50 is a diagram illustrating an example of thespectral distribution of light irradiated from the light source deviceby the electric power supply unit shown in FIG. 47, at the time ofnarrow-band observation.

The fourth embodiment is almost the same as the third embodiment, soonly the differing points will be described, and the same configurationswill be denoted with the same reference numerals and description thereofwill be omitted.

With the light source device according to the present embodiment, theelectric power unit 10 is capable of receiving control signals from thelight adjusting circuit 43 and changing the driving voltage of the xenonlamp 11.

Taking the lamp properties into consideration, the spectral distributionof the light irradiated from the actual light source device is as shownin FIG. 48. Taking into consideration the fact that the energy of thelamp drops at the short wavelength region, and further that the CCDspectral sensitivity properties lose sensitivity in this region, thegain of the B2 band image is excessively increased as a result of coloradjustments processing such as white balance and the like, therebyyielding an image with a very great amount of noise.

Accordingly, with the present embodiment, the light quantity for eachband is adjusted at the light source side so that each band image hasappropriate SN properties even after performing white balance takinginto consideration the spectral properties other than those of thefilter, such as of the lamp, CCD, etc. Note that the bandwidthrestricting filter 92 has the spectral properties shown in FIG. 44.

FIG. 49 illustrates the illumination timing for each band, and the lightquantity control timing at that time. With normal observation whereinthe bandwidth restricting filter 92 is not inserted into the opticalpath, the electric power supply unit 10 receives control signals fromthe light adjusting circuit 43 at an illumination timing indicated by ain FIG. 49 and controls the voltage level of the driving voltage of thexenon lamp 11, and performs light quantity control such as indicated by“b” in FIG. 49. The reason that the quantity of light is decreasedduring the shielding period is to alleviate the heat generated from thelamp.

On the other hand, on the narrow-band observation wherein the bandwidthrestricting filter 92 is inserted in the optical path, the electricpower supply unit 10 receives control signals from the light adjustingcircuit 43 at an illumination timing indicated by “c” in FIG. 49 andcontrols the voltage level of the driving voltage of the xenon lamp 11,and performs light quantity control such as indicated by “d” in FIG. 49.

Thus, according to the present embodiment, in addition to the advantagesof the third embodiment, the spectral distributions of light irradiatedfrom the light source in the event that the voltage level of the drivingvoltage of the xenon lamp 11 is not controlled (see FIG. 48) becomespectral properties such as shown in FIG. 50, so light quantity controlwherein each band image has suitable SN properties can be realized.

FIG. 51 is a configuration diagram illustrating the configuration of anendoscope device according to a fifth embodiment of the presentinvention.

The fifth embodiment is almost the same as the third embodiment, so onlythe differing points will be described, and the same configurations willbe denoted with the same reference numerals and description thereof willbe omitted.

As shown in FIG. 51, with the electronic endoscope 3 according to thepresent embodiment, a color chip 101 is disposed at the front face ofthe CCD 2 to configure a color CCD 2 a, thus configuring the synchronoussystem type endoscope device 1. Color image signals from the color CCD 2a are converted into color image data at the A/D converter 24,subsequently subjected to color separation at the color separatingcircuit 102, then input to the white balance circuit 25, and stored in amemory 103, via the selector 26, subsequently subjected to interpolationprocessing and the like at the image processing circuit 30, followingwhich desired image processing is performed.

The light source device 4 comprises the bandwidth restricting filter 92having multi-peak band-pass properties (see FIG. 38, FIG. 40, FIG. 44),and the bandwidth restricting filter 92 is arranged so as to be insertedto and extracted from the optical path by the filter moving motor 87,based on control signals from the mode switch-over circuit 42 which hasreceived instructions signals from the mode switch-over switch 41.

With the present embodiment thus configured, the bandwidth restrictingfilter 92 is inserted into the optical path, whereby the spectralproperties of the image taken by the CCD 2 via the color chip 101 becomediscrete narrow-band band images (see FIG. 39), and the narrow-band bandimages are subjected to image processing, so the same advantages asthose of the third embodiment can be obtained with the presentembodiment, as well.

FIG. 52 is a configuration diagram illustrating the configuration of anendoscope device according to a sixth embodiment of the presentinvention.

The sixth embodiment is almost the same as the fifth embodiment, so onlythe differing points will be described, and the same configurations willbe denoted with the same reference numerals and description thereof willbe omitted.

With the present embodiment, as shown in FIG. 52, a light source device112 for narrow-band observation is provided separately from a lightsource device 111 for normal observation.

The light source device 111 has the xenon lamp 11 as illumination lightemitting means, and the white light from the xenon lamp 11 passesthrough the diaphragm device 13 and is cast into the incident face ofthe light guide 15 of the electronic endoscope comprising the color CCD2 a.

Also, the light source device 112 has an extra-high pressure mercurylamp 113 as the illumination light emitting means, wherein the lightfrom the extra-high pressure mercury lamp 113 is adjusted at thediaphragm device 13, and is cast into an incident face of anillumination probe 114, inserted into a treatment equipment channel (notshown) of the electronic endoscope 3, via the bandwidth restrictingfilter 92.

Now, the diaphragm device 13 for each of the light source devices 111and 112 are arranged so as to be controlled by the light adjustingcircuit 43 based on control signals from the mode switch-over circuit 42and light adjustment control parameters from the light adjustmentcontrol parameter switch-over circuit 44.

With the present embodiment, at the time of normal observation, thediaphragm device 13 of the light source device 111 is set on the brightside, while the diaphragm device 13 of the light source device 112 isset on the dark side or is shielded.

Also, the time of narrow-band light observation, the diaphragm device 13of the light source device 112 is set on the bright side, while thediaphragm device 13 of the light source device 111 is set on the darkside or is shielded.

Setting each of the diaphragm devices 13 thus means that narrow-bandlight is irradiated from the emitting face of the illumination probe 114at the time of narrow-band light observation, so the same advantages asthose of the fifth embodiment can be obtained with the presentembodiment, as well.

Next, a seventh embodiment of the present invention will be describedwith reference to FIG. 53 to FIG. 57.

FIG. 53 is a configuration diagram illustrating the configuration of anendoscope device, FIG. 54 is a configuration diagram illustrating theconfiguration of the light mixing unit shown in FIG. 53, FIG. 55 is adiagram illustrating an example of spectral distribution of the xenonlamp shown in FIG. 53, FIG. 56 is a diagram illustrating an example ofspectral distribution of the extra-high pressure mercury lamp shown inFIG. 53, and FIG. 57 is a diagram illustrating an example of spectraldistribution of light irradiated from the light source device at thetime of narrow-band observation with the light mixing unit shown in FIG.54.

The seventh embodiment is almost the same as the third embodiment, soonly the differing points will be described, and the same configurationswill be denoted with the same reference numerals and description thereofwill be omitted.

As shown in FIG. 53, the light source device 3 according to the presentembodiment comprises the xenon lamp 11 having a relatively broadspectral distribution as shown in FIG. 55, and the extra-high pressuremercury lamp 113 with multiple emission line spectrums such as shown inFIG. 56 that is provided on the optical path, and further comprises alight mixing unit 121 for mixing the light from the xenon lamp 11 andthe extra-high pressure mercury lamp 113. The light that is mixed at thelight mixing unit 121 is supplied to the electronic endoscope via thediaphragm device 13 and rotating filter 91.

As shown in FIG. 54, the light mixing unit 121 comprises a diaphragm 122for adjusting the light quantity of light from the xenon lamp 11, adiaphragm 123 for adjusting the light quantity of light from theextra-high pressure mercury lamp 113, a half mirror 124 for synthesizingthe light coming through the diaphragm 122 and diaphragm 123, andoutputting onto the optical path of the diaphragm device 13 and rotatingfilter 91, and a diaphragm control circuit 125 for controlling thediaphragm 122 and the diaphragm 123 based on control signals from themode switch-over circuit 42.

When performing narrow-band observation, the diaphragm 122 at the frontface of the xenon lamp 11 is closed by the diaphragm control circuit125, and the diaphragm 123 at the front face of the extra-high pressuremercury lamp 113 is opened, so that the illumination light emitted fromthe light mixing unit has spectral properties equivalent to those of theextra-high pressure mercury lamp 113. This light is then transmittedthrough an R1G1B1 rotating filter 91, consequently irradiating RGBnarrow-band frame sequence light such as shown in FIG. 57 into theliving body tissue.

On the other hand, at the time of normal observation, the diaphragm 122at the front face of the extra-high pressure mercury lamp 113 is closedby a diaphragm control circuit 125, and the diaphragm 123 at the frontface of the xenon lamp 11 is opened, so that RGB frame sequence lightwith natural color reproduction is irradiated on the living body tissue.

According to such an embodiment, the same advantages as those of thethird embodiment can be obtained.

Now, for obtaining intermediate illumination light between the xenonlamp and the extra-high pressure mercury lamp 113, adjusting the degreeof opening of the diaphragms at the front face of both the lamps mixesboth lamp properties at a percentage corresponding to the ratio ofopening the diaphragms, thereby yielding illumination light havingspectral properties differing from either of the lamps.

Also, the actions of the light adjusting circuit 43 are changed by thelight adjustment control parameters changing the light adjusting tableaccording to switching over of the mode, and the change in the spectraldistribution of the illumination light compensates for the change in thequantity of illumination light. Consequently, images which areconstantly of a suitable brightness can be observed even when switchingover to illumination light spectral distributions suiting such an objectas observing the surface structure of mucous membranes in detail.

FIG. 58 is a configuration diagram illustrating the configuration of anendoscope device according to an eighth embodiment of the presentinvention.

The eighth embodiment is almost the same as the first embodiment, soonly the differing points will be described, and the same configurationswill be denoted with the same reference numerals and description thereofwill be omitted.

As shown in FIG. 58, the present embodiment is a narrow-band observationendoscope device having a narrow-band light source device 131 dedicatedfor supplying narrow-band frame sequence light to the electronicendoscope 3, and a narrow-band video processor 132 dedicated forprocessing the narrow-band frame sequence light captured by theelectronic endoscope 3

A narrow-band rotating filter 133 provided in the light source device131 is configured of the R2 filter 14 r 2, G2 filter 14 g 2, and B2filter 14 b 2 (see FIG. 4), for generating narrow-band RGB framesequence light.

Thus, the present embodiment also enables narrow-band observation withnarrow-band frame sequence light.

Also, in the event that the narrow-band light source device 131 havingthe narrow-band rotating filter 133 is connected to the narrow-bandvideo processor 132, information relating to the type of illuminationlight spectral properties of the narrow-band light source device 131 areoutput from the control circuit 17 of the narrow-band illumination lightdevice 131 to the light adjustment control parameter switch-over circuit44, as identification signals. The correlation between theidentification signals and the control parameters is recorded in thelight adjustment parameter switch-over circuit 44 beforehand in the formof a correlation table, and appropriate control signals are output tothe light adjusting circuit 43 based on the correlation table, andconsequently, light adjustment control according to the illuminationlight spectral properties is enabled.

FIG. 59 and FIG. 60 relate to a ninth embodiment of the presentinvention, wherein FIG. 59 is a configuration diagram illustrating theconfiguration of an endoscope device, and FIG. 60 is a diagramillustrating an adapter having a band restricting filter which ismountable on the tip of the electronic endoscope shown in FIG. 59.

The ninth embodiment is almost the same as the first embodiment, so onlythe differing points will be described, and the same configurations willbe denoted with the same reference numerals and description thereof willbe omitted.

As shown in FIG. 59, the present embodiment comprises a normalobservation electronic endoscope 151, an endoscope device 154 having alight source device 152 for supplying normal observation frame sequencelight to the electronic endoscope 151 and a video processor 153 forperforming signal processing on image-pickup signals from the electronicendoscope 151, and a narrow-band light observation endoscope device 155provided separately from this endoscope device 154. Here, this lightsource device 152 has the xenon lamp 11 and diaphragm device 13, and therotating filter 91 upon which are disposed the R1 filter 14 r 1, G1filter 14 g 1, and B1 filter 14 b 1.

The narrow-band light observation endoscope device 155 comprises asmall-diameter electronic endoscope 156 to be inserted through thetreatment equipment channel of the electronic endoscope 151, a lightsource device 157 for supplying narrow-band frame sequence light to thesmall-diameter electronic endoscope 156, and a video processor 158 forsignal processing image-pickup signals from the small-diameterelectronic endoscope 156. The light source device 152 has the extra-highpressure mercury lamp 113 and diaphragm device 13, and a rotating filter160 upon which are disposed the R2 filter 14 r 2, G2 filter 14 g 2, andB2 filter 14 b 2.

Normal observation is performed using the endoscope device 154, andnarrow-band light observation is performed using the narrow-band lightobservation endoscope device 155.

According to the present embodiment, the same advantages as those of thefirst embodiment can be obtained.

Further, a normal endoscope can be connected to the narrow-band lightobservation endoscope device 155.

Also, an adapter 171 having a bandwidth restricting filter 170 such asshown in FIG. 58 may be mounted on the tip of the above-describedelectronic endoscope. Thus, narrow-band light observation can beperformed using the endoscope device 154.

Also, while FIG. 60 is an example of mounting the adapter 171 to whichis applied the bandwidth restricting filter 170 on the front face of theobjective optical system 21, an arrangement may be made wherein thebandwidth restricting filter 170 is mounted in the front face of anillumination lens 172.

As described above, according to the above first through ninthembodiments, tissue information of a desired depth near the tissuesurface of living body tissue can be obtained.

Next, a tenth embodiment of the present invention will be described withreference to FIG. 61 through FIG. 74.

FIG. 61 is a configuration diagram illustrating the configuration of anendoscope device, FIG. 62 is a configuration diagram illustrating theconfiguration of the rotating filter shown in FIG. 61, FIG. 63 is adiagram illustrating the spectral properties of a first filter set ofthe rotating filter shown in FIG. 62, FIG. 64 is a diagram illustratingthe spectral properties of a second filter set of the rotating filtershown in FIG. 62, FIG. 65 is a diagram illustrating the structure of theliving body tissue to be observed with the endoscope device shown inFIG. 1, in the layer direction, FIG. 66 is a diagram describing thestate of the illumination light from the endoscope device shown in FIG.61 reaching the living body tissue in the layer direction, FIG. 67 is adiagram illustrating each of the band images from frame sequence lighttransmitted through the first filter set shown in FIG. 63, FIG. 68 is adiagram illustrating each of the band images from frame sequence lighttransmitted through the second filter set shown in FIG. 64, FIG. 69 is adiagram describing light adjustment control by a light adjusting circuitshown in FIG. 61, FIG. 70 is a configuration diagram illustrating theconfiguration of the image processing circuit shown in FIG. 61, FIG. 71is a diagram illustrating a color image of a narrow-band RGB imageobtained by the image processing circuit shown in FIG. 70, FIG. 72 is adiagram describing the creation of a matrix such that an average colortone is maintained in the 3×3 matrix circuit shown in FIG. 70, FIG. 73is a diagram illustrating an example of settings of the LUT shown inFIG. 70, and FIG. 74 is a configuration diagram illustrating theconfiguration of a modification made to the color conversion processingcircuit shown in FIG. 70.

As shown in FIG. 61, an endoscope device 201 according to the presentembodiment comprises an electronic endoscope 203 having a CCD 202serving as image-pickup means to be inserted into the body cavity andcapture images of tissue within the body cavity, a light source device204 for supplying illumination light to the electronic endoscope, and avideo processor 207 for performing signal processing on image-pickupsignals from the CCD 202 of the electronic endoscope 203 and displayingendoscopic images on an observation monitor 205 or encoding theendoscopic images and outputting to an image filing device 206 ascompressed images.

The light source device 204 is configured of a xenon lamp 211 foremitting illumination light, a heat ray cut filter 212 for shieldingheat rays from the white light, a diaphragm device 213 for controllingthe light quantity of the white light through the heat ray cut filter212, a rotating filter 214 for turning the illumination light into framesequence light, a condenser lens 216 for collecting the frame sequencelight coming through the rotating filter 214 onto the incident face of alight guide 215 disposed within the electronic endoscope 203, and acontrol circuit 217 for controlling the rotation of the rotating filter214.

As shown in FIG. 62, the rotating filter 214 is formed in a disk-likeshape and has a double structure with the center as the rotating axis,wherein an R1 filter 214 r 1, a G1 filter 214 g 1, and a B1 filter 214 b1 making up a first filter set for outputting frame sequence lighthaving overlapping spectral properties suitable for natural colorreproduction such as indicated in FIG. 63 situated on the outer sector,and wherein an R2 filter 214 r 2, a G2 filter 214 g 2, and a B2 filter214 b 2 making up a second filter set for outputting narrow-band framesequence light having discrete spectral properties enabling extractionof desired deep tissue information such as indicated in FIG. 64 situatedon the inner sector. As shown in FIG. 61, the rotating filter 214 isrotated by the control circuit 217 performing driving control of arotating filter motor 218, and movement in the radial direction(movement which is perpendicular to the optical path of the rotatingfilter 214, which is selectively moving the first filter set or secondfilter set of the rotating filter 214 onto the optical path) isperformed by a mode switch-over motor 219 by control signals from a modeswitch-over circuit 242 within the later-described video processor 207.

Note that electric power is applied to the xenon lamp 211, diaphragmdevice 213, rotating filter motor 218, and mode switch-over motor 219,from an electric power supply unit 210.

Returning to FIG. 61, the video processor 207 is configured comprising:a CCD driving circuit 220 for driving the CCD 202; an amplifier 222 foramplifying image-pickup signals wherein images are captured from thebody cavity tissue by the CCD 202 through an objective optical system221; a process circuit 223 for performing correlated double sampling andnoise reduction and so forth, with regard to image-pickup signals comingthrough the amplifier 222; an A/D converter 224 for converting theimage-pickup signals passing through the process circuit 223 into imagedata of digital signals; a white balance circuit 225 for subjecting theimage data from the A/D converter 224 to white balance processing; theselector 226 and synchronizing memory 227 a, 227 b, and 227 c, forsynchronizing the frame sequence light from the rotating filter 214; animage processing circuit 230 for reading out each set of image data ofthe frame sequence light stored in the synchronizing memory 227 a, 227b, 227 c, and subjecting these to gamma correction processing, outlineenhancement processing, color processing, etc; D/A circuits 231 a, 231b, and 231 c, for converting the image data from the image processingcircuit 230 into analog signals; an encoding circuit 234 for encodingthe output of the D/A circuits 231 a, 231 b, and 231 c; and a timinggenerator 235 for inputting synchronizing signals synchronized with therotation of the rotating filter 214 from the control circuit 217 of thelight source device 204, and outputting various types of timing signalsto the above-described circuits.

Also, a mode switch-over switch 241 is provided in the electronicendoscope 203, with the output of this mode switch-over switch 241 beingoutput to the mode switch-over circuit 242 within the video processor207. The mode switch-over circuit 242 of the video processor 207 outputscontrol signals to a light adjusting circuit 243, a light adjustmentcontrol parameter switch-over circuit 244, and mode switch-over motor219 of the light source device 204. The light adjustment controlparameter switch-over circuit 244 outputs light adjustment controlparameters corresponding to the first filter set or second filter set ofthe rotating filter 214 to the light adjusting circuit 243, and thelight adjusting circuit 243 controls the diaphragm device 213 of thelight source device 204 based on the control signals from the modeswitch-over circuit 242 and light adjustment parameters from the lightadjustment control parameter switch-over circuit 244, so as to performappropriate brightness control.

As shown in FIG. 65, a body cavity tissue 251 often has a structurewherein there is a distribution of different absorbent material such asblood vessels in the depth direction, for example. There is primarily agreater distribution of capillaries 252 near the surface of mucusmembranes, blood vessels 253 which are thicker than the capillaries arealso distributed along with capillaries at the middle layer which isdeeper than this layer, and even thicker blood vessels 254 aredistributed at even deeper layers.

On the other hand, the permeation depth of the light in the depthdirection as to the body cavity tissue 251 is dependent on thewavelength of light, and with illumination light containing the visibleregion, as shown in FIG. 66, in the case of light with a shortwavelength such as blue (B), the light only reaches around the surfacelayer due to the absorption properties and scattering properties at theliving body tissue, being subjected to absorption and scattering withinthe range up to that depth, so light coming out from the surface isobserved. Also, in the case of green (G) light with a wavelength longerthan that of blue (B) light, the light reaches a depth deeper than therange where the blue (B) light reaches, is subjected to absorption andscattering within the range at that depth, and light coming out from thesurface is observed. Further, red (R) light with a wavelength longerthan that of green (G) light, reaches a range even deeper.

At the time of performing normal observation, the mode switch-overcircuit within the video processor 207 controls the mode switch-overmotor 219 with control signals, so that the R1 filter 214 r 1, G1 filter214 g 1, and B1 filter 214 b 1, making up the first filter set of therotating filter 214, are positioned on the optical path of theillumination light.

With the R1 filter 214 r 1, G1 filter 214 g 1, and B1 filter 214 b, thewavelength regions are each overlapped as shown in FIG. 63, so at thetime of normal observation of the body cavity tissue 251, a band imagehaving shallow layer and middle layer tissue information containing agreat amount of tissue information at the shallow layer such as shown by“a” in FIG. 67 is captured in the image-pickup signals which arecaptured by the CCD 202 with the B1 filter 214 b 1, a band image havingshallow layer and middle layer tissue information containing a greatamount of tissue information at the middle layer such as shown in “b” inFIG. 67 is captured into the image-pickup signals that are captured bythe CCD 202 with the G1 filter 214 g 1, and further, a band image havingmiddle layer and deep layer tissue information containing a great amountof tissue information at the deep layer such shown in “c” in FIG. 67 iscaptured into the image-pickup signals which are captured by the CCD 202with the R1 filter 214 r 1.

These RGB image-pickup signals are synchronized with the video processor207 and subjected to signal processing, thus enabling an endoscopicimage with desired or natural color reproduction to be obtained as anendoscopic image.

On the other hand, upon the mode switch-over switch 241 of theelectronic endoscope 203 being pressed, the signals thereof are inputinto the mode switch-over circuit 242 of the video processor 207. Themode switch-over circuit 242 outputs control signals to the modeswitch-over motor 219 of the light source device 204, thereby moving thefirst filter set of the rotating filter 214 that was on the optical pathat the time of normal observation, and drives the rotating filter 214with respect to the optical path so that the second filter set ispositioned upon the optical path.

In the event of performing narrow-band light observation of the bodycavity tissue 251 with the second filter set, the R2 filter 214 r 2, G2filter 214 g 2, and B2 filter 214 b 2 make the illumination light to benarrow-band frame sequence light with discrete spectral properties asshown in FIG. 64, so a band image having tissue information at a shallowlayer such as shown in “a” in FIG. 68 is captured into the image-pickupsignals which are captured by the CCD 202 with the B2 filter 214 b 2, aband image having tissue information at the middle layer such as shownin “b” in FIG. 68 is captured into the image-pickup signals which arecaptured by the CCD 202 with the G2 filter 214 g 2, and a band imagehaving tissue information at the deep layer such as shown in “c” in FIG.68 is captured into the image-pickup signals which are captured by theCCD 202 with the R2 filter 214 r 2.

As can be clearly understood from FIG. 63 and FIG. 64, at this time, thequantity of transmitted light from the second filter set is less thanthe quantity of transmitted light from the first filter set, because thebands thereof are narrowed, so the light adjusting circuit 243 controlsthe diaphragm device 213 by outputting light adjustment controlparameters according to the first filter set or second filter set of therotating filter 214, from the light adjustment control parameterswitch-over circuit 244 to the light adjusting circuit 243, thereby, asshown in FIG. 69, controlling the diaphragm device 213 when makingnarrow-band light observation so as to control light quantity Mx with adiaphragm control curve 262 corresponding to a set value Lx, withrespect to, for example, a linear diaphragm control line 261 by thediaphragm device 213 in normal observation, corresponding to the setvalue Lx on an unshown setting panel of the video processor 207. Thus,image data with sufficient brightness can be obtained at the time ofnarrow-band light observation, as well.

Specifically, the aperture level value corresponding to the lightquantity setting value Lx changes from Mx1 to Mx2 as shown in FIG. 69,being interlocked with changing the first filter set to the secondfilter set, and consequently, the diaphragm is controlled in thedirection of being opened, and acts to compensate for reduction in thequantity of illumination light by the filters which narrows the band.

As shown in FIG. 70, an image processing circuit 230 comprises threesets each of LUTs 262 a, 262 b, 262 c, 263 a, 263 b, and 263 c, fore andaft, across a 3×3 matrix circuit 261, and a coefficient changing circuit264 for converting table data of the LUTs 262 a, 262 b, 262 c, 263 a,263 b, and 263 c, and the coefficients of the 3×3 matrix circuit 261,thus configuring a color conversion processing circuit 230 a.

The RGB data input to the color conversion processing circuit 230 a isconverted by the LUTs 262 a, 262 b, and 262 c, for each band data. Here,inverse γ correction, non-linear contrast conversion, etc., isperformed.

Next, following color conversion being performed at the 3×3 matrixcircuit 261, γ correction and suitable tone conversion processing isperformed at the latter LUTs 263 a, 263 b, and 263 c.

Change can be made at a coefficient changing circuit 264 for convertingtable data of the LUTs 262 a, 262 b, 262 c, 263 a, 263 b, and 263 c, andthe coefficients of the 3×3 matrix circuit 261.

Changing with the coefficient changing circuit 264 is based on controlsignals from the mode switch-over circuit 242 or a processing conversionswitch (not shown) provided on the operating unit or the like of theelectronic endoscope 203.

Upon receiving the control signals, the coefficient changing circuit 264calls up appropriate data from the coefficient data described in theimage processing circuit 230 beforehand, and rewrites the currentcircuit coefficients with this data.

Next, the contents of color conversion processing will be describedspecifically. Expression 1 shows an example of a color conversionexpression.

Expression 1

R→R

G→ω _(G) G+ω _(B) B

B→B  (1)

The processing according to Expression 1 is an example of conversion fortaking data generated by a B image having been mixed with G at a certainratio and taking this anew as a G image. Making the illumination lightfor each band to be narrow-band can further clarify that absorbents andscatterers such as blood vessel networks differ according to depthposition.

That is to say, the difference in information relating to bodystructures which each band reflect can be further increased by makingthe illumination light to be narrow-band.

In the event of observing these narrow-band RGB images as color images,this will be an image such as shown in FIG. 71, for example. The thickblood vessels are at deep positions, and are reflected in the R bandimage, indicated by a blue color pattern as the color thereof. The bloodvessel network near the middle layers is intensely reflected in the Gimage, and is indicated as a red color pattern for the color imagethereof. Of the blood vessel networks, those existing near the surfaceof the mucous membrane are represented as a yellow color pattern.

Particularly, the change in pattern near the surface of the mucousmembrane is crucial for early discovery and differential diagnosis ofearly disorders. However, yellow patterns have little contrast with thebackground mucous membrane, and accordingly the visibility thereof tendsto be low.

Accordingly, the conversion shown in Expression 1 is valid for clearlyreproducing the patterns near the surface of the mucous membrane.Expression 1 can be expressed in matrix format as shown in Expression 2.

$\begin{matrix}\text{Expression~~2} & \; \\{\begin{pmatrix}R^{\prime} \\G^{\prime} \\B^{\prime}\end{pmatrix} = {\begin{pmatrix}1 & 0 & 0 \\0 & \omega_{G} & \omega_{B} \\0 & 0 & 1\end{pmatrix}\begin{pmatrix}R \\G \\B\end{pmatrix}}} & (2)\end{matrix}$

Accordingly, adjusting the matrix coefficients through the coefficientchanging circuit 264 allows the user to adjust the display effects. Asfor the operations, synchronously with a mode switch-over switch (notshown) provided to the operating unit of the electronic endoscope 203,the matrix coefficients are set to default values from a throughoperation within the image processing means.

The through operation here refers to a state wherein the 3×3 matrixcircuit 261 carries a unit matrix, and the LUTs 262 a, 262 b, 262 c, 263a, 263 b, and 263 c carry non-conversion tables. Default values are toprovide the matrix coefficients with set values of, for example, ωG=0.2,ωB=0.8.

The user then operates a processing changing switch or the like providedto the operating unit of the electronic endoscope 203 or the videoprocessor casing panel or the like, and performs adjustment so that thecoefficients are ωG=0.4, ωB=0.6, and so forth. If necessary, inverse γcorrection tables and γ correction tables are applied to the LUTs 262 a,262 b, 262 c, 263 a, 263 b, and 263 c.

Next, description will be made wherein color correction is performed soas to maintain an average color tone as much as possible even in theevent that the filter is switched, at the color conversion processingcircuit 230 a.

As a result of filter switching, the spectral properties of theillumination light change. Consequently, color reproduction alsochanges. Depending on the state of usage or the user, there may be caseswherein maintaining average color reproduction as much as possible isdesired while maintaining improved contrast of minute structure at thesurface of the mucous membrane. In such cases, there is the need tochange the operations by the coefficient changing circuit 264 so as toperform color conversion operations wherein the average color tone ismaintained from the through operation, in accordance with the filterswitching.

Procedures for creating a matrix for maintaining average color tone areshown below. As shown in FIG. 72, let us say that the color distributionof a subject in an RGB color space moves from a first distribution to asecond distribution, corresponding to filter switching. In such a case,at least three points are selected from the first distribution (normallycontaining distribution average and center-of-gravity data), and wherein the second distribution these three points move to is checked. Then,a conversion matrix from the second distribution to the firstdistribution is calculated using the three sets of data, and used as thematrix coefficients for the 3×3 matrix circuit 261. Note that three ormore points can be selected and determined by the method ofleast-squares.

Color reproduction which maintains average color tone as much aspossible can be attained even when switching filters, by applying theabove matrix coefficients to the LUTs 262 a, 262 b, 262 c, 263 a, 263 b,and 263 c, using inverse γ correction and γ correction tables asnecessary.

Also, image effects such as pigment dying can be reproduced with a Bimage alone, taking advantage of the fact that the narrow-band B imagereflects the minute structures of the surface of mucous membranes well,such as pit patterns. That is to say, the output RGB data is configuredof only the B data out of the RGB data input by the matrix conversionexpression indicated in Expression 3.

$\begin{matrix}\text{Expression~~3} & \; \\{\begin{pmatrix}R^{\prime} \\G^{\prime} \\B^{\prime}\end{pmatrix} = {\begin{pmatrix}0 & 0 & \omega_{R} \\0 & 0 & \omega_{G} \\0 & 0 & \omega_{B}\end{pmatrix}\begin{pmatrix}R \\G \\B\end{pmatrix}}} & (3)\end{matrix}$

Adjusting the coefficients then allows effects such as pigment dyingimages to be exhibited. For example, with settings wherein ωB >>ωG, ωR,the image exhibits a bluish tone, and has the tone of the same color asperforming indigo dying. Also, with settings wherein ωB, ωR >>ωR, theimage exhibits a purplish tone, and has the tone of the same color asperforming methyl violet dying. Further, setting the LUT settings suchas shown in FIG. 73 results in hard reproduction for the contrast, andimages with high contrast such as with dyed images can be obtained.

Thus, according to the present embodiment, setting the parameters of thecolor conversion processing circuit 230 a synchronously with the filterswitching allows a representation method which takes advantage of thecharacteristic of narrow-band RGB illumination light, namely, permeationdepth information, to be realized, so tissue information at desireddepths near the tissue surface of living body tissue can be separatedand visually recognized.

Now, with the above embodiment, the color conversion processing circuit230 a is described as a configuration with the 3×3 matrix circuit 261 atthe center, but the same advantages can be obtained by replacing thecolor conversion processing circuit 230 a with 3-dimensional LUTs 271corresponding to each band, as shown in FIG. 74. In this case, thecoefficient changing circuit 264 performs operations for changing thecontents of the tables based on control signals from the modeswitch-over circuit 242.

Next, an eleventh embodiment of the present invention will be describedwith reference to FIG. 75 through FIG. 78.

FIG. 75 is a configuration diagram illustrating the configuration of anendoscope device, FIG. 76 is a configuration diagram illustrating theconfiguration of the image processing circuit shown in FIG. 75, FIG. 77is a configuration diagram illustrating the configuration of the coloradjusting circuit shown in FIG. 75, and FIG. 78 is a diagramillustrating the concept of hue and saturation on a L*a*b* color spacein the color adjusting circuit shown in FIG. 75.

The eleventh embodiment is almost the same as the tenth embodiment, soonly the differing points will be described, and the same configurationswill be denoted with the same reference numerals and description thereofwill be omitted.

With the present embodiment, a case including means for convertingcoordinates between a color space such as XYZ which is not dependent ona device such as a monitor, and a color space such as RGB which isdependent on a device, is shown as color conversion of a colorconversion processing circuit for changing operations synchronously withoperations of filter switching.

As shown in FIG. 75, a processing switch-over instructing switch 281 isprovided in the electronic endoscope 203, with the image processingcircuit 230 receiving control signals from the mode switch-over circuit242 and instruction signals from the processing switch-over instructingswitch 281, and performing the later-described color conversionprocessing.

As shown in FIG. 76, a color conversion processing circuit 230 bconfigured in the image processing circuit 230 comprises LUTs 282 a, 282b, and 282 c, which are set for each band, a 3×3 matrix circuit 283, acolor adjusting circuit 284, a subsequent stage 3×3 matrix circuit 285,subsequent LUTs 286 a, 286 b, and 286 c, which are set for each band,and the coefficient changing circuit 264.

RGB data which is first input to the preliminary LUTs 282 a, 282 b, and282 c is subjected to inverse γ correction. This is to cancel non-linearγ correction which is performed taking into consideration the γproperties of the display device such as a CRT, before color conversionprocessing.

Next, conversion is made at the preliminary 3×3 matrix circuit 283, fromRGB to XYZ which is a color space that is not device-dependent. Theconversion expression is shown in Expression 4.

In Expression 4, xi, yi, and zi (i=R, G, B) are xy chromaticitycoordinates of the primitive colors of the display device such as a CRTor the like.

$\begin{matrix}\text{Expression~~4} & \; \\{\begin{pmatrix}X \\Y \\Z\end{pmatrix} = {\begin{pmatrix}\frac{x_{R}}{y_{r}} & \frac{x_{G}}{y_{G}} & \frac{x_{B}}{y_{B}} \\1 & 1 & 1 \\\frac{z_{R}}{y_{R}} & \frac{z_{G}}{y_{G}} & \frac{z_{B}}{y_{B}}\end{pmatrix}\begin{pmatrix}R \\G \\B\end{pmatrix}}} & (4)\end{matrix}$

Next, following being subjected to later-described appropriate coloradjustment at the color adjusting circuit 284, conversion is made intodevice-dependent color space R′G′B′ again at the subsequent stage 3×3matrix circuit 285 by Expression 5, and following γ correction formonitor display at the subsequent LUTs, output is made to theobservation monitor 205.

$\begin{matrix}\text{Expression~~5} & \; \\{\begin{pmatrix}R^{\prime} \\G^{\prime} \\B^{\prime}\end{pmatrix} = {\begin{pmatrix}\frac{x_{R}}{y_{r}} & \frac{x_{G}}{y_{G}} & \frac{x_{B}}{y_{B}} \\1 & 1 & 1 \\\frac{z_{R}}{y_{R}} & \frac{z_{G}}{y_{G}} & \frac{z_{B}}{y_{B}}\end{pmatrix}^{- 1}\begin{pmatrix}(X)^{\prime} \\(Y)^{\prime} \\(Z)^{\prime}\end{pmatrix}}} & (5)\end{matrix}$

Next, the operations of the color adjusting circuit 284 will bedescribed. As shown in FIG. 77, the color adjusting circuit 284comprises a sensory color space conversion unit 287 which performsconversion from XYZ to a sensory color space such as L*a*b*, a hue andsaturation conversion adjusting unit 288 which performs conversion tohue and saturation which humans perceive to be the three attributes ofcolor, adjusts these values and performs intuitive color adjustment, andthen performs inverse conversion to L*a*b*, and a sensory color inverseconversion unit 289 for performing conversion to XYZ again.

Expression 6 shows the conversion expression between L*a*b* and XYZ, andfurther, Expression 7 shows the conversion expression from L*a*b* to hueHab and Cab. Here, X_(w), Y_(w), and Z_(w) represent the XYZ values forreference white.

$\begin{matrix}\text{Expression~~6} & \; \\{{L^{*} = {{116( \frac{Y}{Y_{w}} )^{\frac{1}{3}}} - 16}}{a^{*} = {500\lbrack {( \frac{X}{X_{w}} )^{\frac{1}{3}} - ( \frac{Y}{Y_{w}} )^{\frac{1}{3}}} \rbrack}}{b^{*} = {200\lbrack {( \frac{X}{X_{w}} )^{\frac{1}{3}} - ( \frac{Z}{Z_{w}} )^{\frac{1}{3}}} \rbrack}}} & (6) \\\text{Expression~~7} & \; \\{{C_{ab} = \sqrt{a^{*2} + b^{*2}}}{H_{ab} = {\arctan ( \frac{b^{*}}{a^{*}} )}}} & (7)\end{matrix}$

Also, FIG. 78 illustrates the concepts of hue and saturation in a L*a*b*color space.

Once converted into hue and saturation, color adjustment can beperformed intuitively. For example, if a brighter color tone is desired,this can be achieved by multiplying or adding the saturation with aconstant coefficient. Also, in the event that change of the color towardblue or toward red is desired, the hue value can be adjusted. Thus,intuitive color adjustment can be realized at the color adjusting means.

Next, operations interlocked with the mode switch-over circuit 242 andthe processing switch-over instructing switch 281 will be described. Acharacteristic of observation with narrow-band RGB illustration light isthat, in the event that there are different structures in the depthdirection of the body, such as blood vessel structures, these arerepresented with different colors. Even more effective display can bemade by enhancing the saturation and rotating the hue as suitable inorder to enhance these characteristics even more.

Accordingly, being interlocked with the mode switch-over circuit 242,the coefficient changing circuit 264 changes the coefficients of therelated circuit based on instruction signals from the processingswitch-over instructing switch 281, so that through passage is allowedwithout color adjustment when performing normal observation for example,and color adjustment is made for narrow-band observation. Further, inthe event of observation with narrow-band RGB illumination light, thedegree of enhancement of saturation and the degree of rotation of hue isswitched over according to user preferences, the type of subject, etc.,by instructions of the processing switch-over instructing switch 281.

Also, the conversion from RGB to XYZ has been performed with anexpression based on a normal CRT device model, but may be changed to theone as shown in Expression 8 with regard to a calculation method of theluminance Y, of XYZ.

In Expression 8, change has been made such that the RGB ratio can bespecified at the time of calculating Y.

$\begin{matrix}\text{Expression~~8} & \; \\{\begin{pmatrix}X \\Y \\Z\end{pmatrix} = {\begin{pmatrix}\frac{x_{R}}{y_{r}} & \frac{x_{G}}{y_{G}} & \frac{x_{B}}{y_{B}} \\\omega_{R} & \omega_{G} & \omega_{B} \\\frac{z_{R}}{y_{R}} & \frac{z_{G}}{y_{G}} & \frac{z_{B}}{y_{B}}\end{pmatrix}\begin{pmatrix}R \\G \\B\end{pmatrix}}} & (8)\end{matrix}$

The B image of narrow-band RGB has a characteristic of minute structuresof the body mucous membrane surface being reflected with high contrast.In order to reflect this information in the luminance information, theweight ωB of B is increased at the time of calculating Y. Generally, theluminance of B is low as compared to RG (G is the greatest for humanluminance sensitivity), so calculating using Expression 6 with no changedoes not reflect the information of B very much. Accordingly, it ismeaningful to adjust the weight of B as described above.

Each of the band images reflect different body structures withnarrow-band RGB images, so the weight can be adjusted with Expression 8according to objects of use. It is sufficient that multiple types ofweight combinations be prepared beforehand, so as to be switched overunder control of the processing switch-over switch. Incidentally,Expression 7 is used for inverse conversion from XYZ to RGB in thiscase.

Thus, with the present embodiment, as with the tenth embodiment, arepresentation method which takes advantage of the characteristic ofpermeation depth information of narrow-band RGB illumination light canbe realized by setting the parameters of the color converting processingcircuit 230 a synchronously with the filter switching, and accordingly,tissue information at desired depths near the tissue surface of livingbody tissue can be separated and visually recognized.

Next, a twelfth embodiment of the present invention will be describedwith reference to FIG. 79 through FIG. 84.

FIG. 79 is a configuration diagram illustrating the configuration of anendoscope device, FIG. 80 is a configuration diagram illustrating theconfiguration of the rotating filter shown in FIG. 79, FIG. 81 is adiagram illustrating the spectral transmission properties of the filtersG2, B2 a, and B2 b, of the rotating filter shown in FIG. 80, FIG. 82 isa configuration diagram illustrating the configuration of the bandselecting circuit shown in FIG. 79, FIG. 83 is a configuration diagramillustrating the configuration of a modification made on the rotatingfilter shown in FIG. 79, and FIG. 84 is a diagram illustrating spectraltransmission properties of the rotating filter shown in FIG. 83.

The twelfth embodiment is almost the same as the tenth embodiment, soonly the differing points will be described, and the same configurationswill be denoted with the same reference numerals and description thereofwill be omitted.

As shown in FIG. 79, the present embodiment comprises four pieces ofsynchronizing memory 227 a, 227 b, 227 c, and 227 d, for the output of aselector 226, the image processing circuit 230 which performs imageprocessing with regard to the output of the four pieces of synchronizingmemories 227 a, 227 b, 227 c, and 227 d, D/A circuits 231 a, 231 b, 231c, and 231 d, which convert the four sets of data processed by the imageprocessing circuit 230 into analog data, and a band selecting circuitfor subjecting the output of the D/A circuits 231 a, 231 b, 231 c, and231 d to matrix computation and outputting as three bands of data.

The reason that there are four sets of synchronizing memory is that thesecond filter set of the double-structure rotating filter 214 isconfigured of filters with four bandwidths, R2, G2, B2 a, and B2 b asshown in FIG. 80, and the spectral transmittance properties of thesefilters R2, G2, B2 a, and B2 b are as shown in FIG. 81.

In the event that the rotating filter 214 is specified to the secondfilter set (R2, G2, B2 a, and B2 b) by control signals of the modeswitch-over circuit 242 by control signals from the mode switch-overinstructing switch 241, the four band images are input to the fourpieces of synchronizing memories 227 a, 227 b, 227 c, and 227 d. Thefour band images are subjected to processing such as color adjustmentand the like at the image processing circuit 230, then subjected to D/Aconversion at the D/A circuits 231 a, 231 b, 231 c, and 231 d, and theninput to a band selecting circuit 301.

The user uses a band switch-over instructing switch 302 provided on theoperating unit of the electronic endoscope 203 to specify which band ofthe four bands will be used to output an image to the observationmonitor 205.

As shown in FIG. 82, the band selecting circuit 301 is configured of a4×3 matrix circuit 305 and a matrix coefficient changing circuit 306,wherein band switch-over instructing signals output from the bandswitch-over instructing switch 302 are input to the matrix coefficientchanging circuit 306 provided to the band selecting circuit 301. Thematrix coefficient changing circuit 306 applies predetermined matrixcoefficients to the 4×3 matrix circuit 305, based on the bandswitch-over instructing signals.

Expression 9 shows a matrix circuit expression.

$\begin{matrix}\text{Expression~~9} & \; \\{\begin{pmatrix}d_{r} \\d_{g} \\d_{b}\end{pmatrix} = {\begin{pmatrix}w_{11} & w_{12} & w_{13} & w_{14} \\w_{21} & w_{22} & w_{23} & w_{24} \\w_{31} & w_{32} & w_{33} & w_{34}\end{pmatrix}\begin{pmatrix}D_{R\; 2} \\D_{G\; 2} \\D_{B\; 2a} \\D_{B\; 2b}\end{pmatrix}}} & (9)\end{matrix}$

As shown in FIG. 9, at the band selecting circuit 301, the 4×3 matrixcoefficients act upon the input values for the four band images (DR2,DG2, DB2 a, and DB2 b) to yield three output signals (dr, dg, and db),and these signals are output to the observation monitor 205 astrichromatic signals.

Expression 10 illustrates an example of matrix coefficients.

$\begin{matrix}\text{Expression~~10} & \; \\{{{M\; 1} = \begin{pmatrix}1 & 0 & 0 & 0 \\0 & 1 & 0 & 0 \\0 & 0 & 1 & 0\end{pmatrix}}{{M\; 2} = \begin{pmatrix}1 & 0 & 0 & 0 \\0 & 1 & 0 & 0 \\0 & 0 & 0 & 1\end{pmatrix}}{{M\; 3} = \begin{pmatrix}0 & 0 & 1 & 0 \\0 & 0 & 1 & 0 \\0 & 0 & 0 & 1\end{pmatrix}}{{M\; 4} = \begin{pmatrix}0 & 0 & 1 & 0 \\0 & 0 & 1 & 0 \\0 & 0 & 1 & 0\end{pmatrix}}{{M\; 5} = \begin{pmatrix}1 & 0 & 0 & 0 \\0 & 1 & 0 & 0 \\0 & 0 & 0.2 & 0.8\end{pmatrix}}} & (10)\end{matrix}$

The coefficients set in M1 configure an image of R2, G2, and B2 a, whileM2 is settings using B2 b instead of B2 a. Switching between M1 and M2can be made by, for example, setting B2 a at a center wavelength ofnear-ultraviolet light, and setting B2 b to a hemoglobin absorbingwavelength band (e.g., 415 nm), thereby enabling using these asdepending on conditions, as a mode for observing minute irregularitiesnear the surface of the mucous membranes such as pit patterns in detailin the event that M1 is applied, and a mode for observing in detailminute capillary networks near the surface of the mucous membranes inthe event that M2 is applied.

Also, the coefficient M3, because the image is configured of the twobands of B2 a and B2 b, is suitable for catching change in scatteringproperties such as change in the cell structure near the surface of themucous membranes and the like, by configuring a narrow-band filter withB2 a and B2 b in close approximation near 380 nm.

Also, in the event that simple observation of a single-color image of acertain band as a monochrome image is desired, the settings may be madeas with M4, or the coefficients may be set as in M5 to mix and outputmultiple bands at a certain ratio so as to take advantage of theproperties of each band.

Thus, according to the present embodiment, in addition to the advantagesof the tenth embodiment, there are no markedly dark portions on thescreen at the time of changing filters to switch over from normalobservation to narrow-band filter observation, and light quantitysufficient to fully enable observation can be obtained. Further, whichband to use for image observation can be selected from the multiplefilters, so optimal observation images according to the state of usagecan be obtained.

Also, though the present embodiment describes the rotating filter 214 asbeing a double structure, the rotating filter can be made a singlestructure in the event that changing the B filter is sufficient forobtaining image effects, thus configuring a rotating filter 214 made upof four filters, as shown in FIG. 83. As for the filter properties,there is a configuration wherein, for example, only the B filter is madenarrow-band, as shown in FIG. 84. The object of this is to takeadvantage of the fact that the permeation depth of light around thiswavelength band to the body is shallow, thereby improving contrast ofbody structures such as blood vessels near the surface by the filterwhich narrows the band. Due to such a configuration for the rotatingfilter 214, the user can obtain optimal observation images by simplyinstructing band switching over according to the state of observation,without switching filters.

As described above, according to the tenth embodiment through twelfthembodiment, tissue information at a desired depth near the tissuesurface of the living body tissue can be separated and visuallyrecognized.

Next, a thirteenth embodiment of the present invention will be describedwith reference to FIG. 85 through FIG. 94.

FIG. 85 is a configuration diagram illustrating the configuration of anendoscope device according to the present invention, FIG. 86 is aconfiguration diagram illustrating the configuration of the rotatingfilter shown in FIG. 85, FIG. 87 is a diagram illustrating the spectralproperties of the first filter set of the rotating filter shown in FIG.86, FIG. 88 is a diagram illustrating the spectral properties of thesecond filter set of the rotating filter shown in FIG. 86, FIG. 89 is adiagram illustrating the structure of the living body tissue in thelayer direction to be observed with the endoscope device shown in FIG.85, FIG. 90 is a diagram describing the state of the illumination lightfrom the endoscope device shown in FIG. 85 reaching the living bodytissue in the layer direction, FIG. 91 is a diagram illustrating each ofthe band images from frame sequence light transmitted through the firstfilter set shown in FIG. 87, FIG. 92 is a diagram illustrating each ofthe band images from frame sequence light transmitted through the secondfilter set shown in FIG. 88, FIG. 93 is a diagram describing lightadjustment control performed by a light adjusting circuit shown in FIG.85, and FIG. 94 is a configuration diagram illustrating theconfiguration of the image processing circuit shown in FIG. 85.

The thirteenth embodiment is almost the same as the tenth embodiment, soonly the differing points will be described, and the same configurationswill be denoted with the same reference numerals and description thereofwill be omitted.

As shown in FIG. 85, the endoscope device 401 according to the presentembodiment is configured of an electronic endoscope 403 which isinserted inside the body cavity and which has a CCD 402 serving asimage-pickup means for capturing images of tissue within the bodycavity, a light source device 404 for supplying illumination light tothe electronic endoscope 403, and a video processor 407 for subjectingimage-pickup signals from the CCD 402 of the electronic endoscope 403 tosignal processing and displaying endoscopic images on an observationmonitor 405 or encoding the endoscopic images and outputting to an imagefiling device 406 as compressed images.

The light source device 404 is configured of a xenon lamp 411 foremitting illumination light, a heat ray cut filter 412 for shieldingheat rays from the white light, a diaphragm device 413 for controllingthe light quantity of the white light through the heat ray cut filter412, a rotating filter 414 for turning the illumination light into framesequence light, a condenser lens 416 for collecting the frame sequencelight coming through the rotating filter 414 onto the incident face of alight guide 415 disposed within the electronic endoscope 403, and acontrol circuit 417 for controlling the rotation of the rotating filter414.

As shown in FIG. 86, the rotating filter 414 is formed in a disk-likeshape and has a double structure with the center as the rotating axis,wherein an R1 filter 414 r 1, a G1 filter 414 g 1, and a B1 filter 414 b1 making up a first filter set for outputting frame sequence lighthaving overlapped spectral properties suitable for natural colorreproduction such as indicated in FIG. 87 are situated on the outersector, and wherein an R2 filter 414 r 2, a G2 filter 414 g 2, and a B2filter 414 b 2 making up a second filter set for outputting narrow-bandframe sequence light having discrete spectral properties enablingextraction of desired deep tissue information such as indicated in FIG.88 are situated on the inner sector. As shown in FIG. 85, the rotatingfilter 414 is rotated by the control circuit 417 performing drivingcontrol of the rotating filter motor 418, and movement in the radialdirection (movement which is perpendicular to the optical path of therotating filter 414, which is selectively moving the first filter set orsecond filter set of the rotating filter 414 onto the optical path) isperformed by the mode switch-over motor 19 by control signals from themode switch-over circuit 442 within the later-described video processor417.

Note that electric power is applied to the xenon lamp 411, diaphragmdevice 413, rotating filter motor 418, and mode switch-over motor 419,from the electric power supply unit 410.

Returning to FIG. 85, the video processor 407 is configured comprising aCCD driving circuit 420 for driving the CCD 402, an amplifier 422 foramplifying image-pickup signals by which images are captured of the bodycavity tissue via the CCD 402 through the objective optical system 421,a process circuit 423 for performing correlated double sampling andnoise reduction and so forth, with regard to image-pickup signals comingthrough the amplifier 422, an A/D converter 424 for converting theimage-pickup signals passing through the process circuit 423 into imagedata of digital signals, a white balance circuit 425 for subjecting theimage data from the A/D converter 424 to white balance processing, aselector 426 and synchronizing memories 427 a, 427 b, and 427 c, forsynchronizing the frame sequence light from the rotating filter 414, animage processing circuit 430 for reading out each set of image data ofthe frame sequence light stored in the synchronizing memories 427 a, 427b, 427 c, and subjecting these to gamma correction processing, outlineenhancement processing, color processing, etc., D/A circuits 431 a, 431b, and 431 c, for converting the image data from the image processingcircuit 430 into analog signals, an encoding circuit 434 encoding theoutput of the D/A circuits 431 a, 431 b, and 431 c, and a timinggenerator 435 for inputting synchronizing signals synchronized with therotation of the rotating filter 414 from the control circuit 417 of thelight source device 404, and outputting various types of timing signalsto the above-described circuits.

Also, a mode switch-over switch 441 is provided in the electronicendoscope 403, with the output of this switch-over switch 441 beingoutput to a mode switch-over circuit 442 within the video processor 407.The mode switch-over circuit 442 of the video processor 407 outputscontrol signals to a light adjusting circuit 443, a light adjustmentcontrol parameter switch-over circuit 444, and mode switch-over motor419 of the light source 404. The light adjustment control parameterswitch-over circuit 444 outputs light adjustment control parameterscorresponding to the first filter set or second filter set of therotating filter 414 to the light adjusting circuit 443, and the lightadjusting circuit 443 controls the diaphragm device 413 of the lightsource device 404 based on the control signals from the mode switch-overcircuit 442 and light adjusting parameters from the light adjustmentcontrol parameter switch-over circuit 444, so as to perform appropriatebrightness control.

As shown in FIG. 89, body cavity tissue 451 often has a structurewherein there is a distribution of different absorbent material such asblood vessels in the depth direction, for example. A great number ofcapillaries 452 are mainly distributed near the surface of mucusmembranes, blood vessels 453 which are thicker than the capillaries arealso distributed along with capillaries at the middle layer which isdeeper than this layer, and even thicker blood vessels 454 aredistributed at even deeper layers.

On the other hand, the permeation depth of the light in the depthdirection as to the body cavity tissue 451 is dependent on thewavelength of light, and with illumination light containing the visibleregion, as shown in FIG. 90, in the case of light with a shortwavelength such as blue (B), the light only reaches around the surfacelayer due to the absorption properties and scattering properties at theliving body tissue, being subjected to absorption and scattering withinthe range up to that depth, and light coming out from the surface isobserved. Also, in the case of green (G) light with a wavelength longerthan that of blue (B) light, the light reaches a depth deeper than therange where the blue (B) light reaches, is subjected to absorption andscattering within the range at that depth, and light coming out from thesurface is observed. Further, red (R) light with a wavelength longerthan that of green (G) light, reaches a range even deeper.

At the time of performing normal observation, the mode switch-over motor419 is controlled by the mode switch-over circuit within the videoprocessor 407 with control signals, so that the R1 filter 414 r 1, G1filter 414 g 1, and B1 filter 414 b 1, making up the first filter set ofthe rotating filter 414, are positioned on the optical path of theillumination light.

With the R1 filter 414 r 1, G1 filter 414 g 1, and B1 filter 414 b, thewavelength regions are each overlapped as shown in FIG. 87, so at thetime of normal observation of the body cavity tissue 451, a band imagehaving shallow layer and middle layer tissue information containing agreat amount of tissue information at the shallow layer such shown in“a” in FIG. 91 is captured in the image-pickup signals taken by the CCD402 with the B1 filter 414 b 1, a band image having shallow layer andmiddle layer tissue information containing a great amount of tissueinformation at the middle layer such as shown in “b” in FIG. 91 iscaptured in the image-pickup signals taken by the CCD 402 with the G1filter 414 g 1, and further, a band image having middle layer and deeplayer tissue information containing a great amount of tissue informationat the deep layer such shown in “c” in FIG. 91 is captured in theimage-pickup signals taken by the CCD 402 with the R1 filter 414 r 1.

These RGB image-pickup signals are synchronized with the video processor407 and subjected to signal processing, thus enabling an endoscopicimage with desired or natural color reproduction to be obtained as anendoscopic image.

On the other hand, upon the mode switch-over switch 441 of theelectronic endoscope 403 being pressed, the signals thereof are input tothe mode switch-over circuit 442 of the video processor 407. The modeswitch-over circuit 442 outputs control signals to the mode switch-overmotor 419 of the light source device 404, thereby moving the firstfilter set of the rotating filter 414 that was on the optical path atthe time of normal observation, and drives the rotating filter 414 withregard to the optical path so that the second filter set is positionedupon the optical path.

In the event of performing narrow-band light observation of the bodycavity tissue 451 with the second filter set, the R2 filter 414 r 2, G2filter 414 g 2, and B2 filter 414 b 2 make the illumination light to benarrow-band frame sequence light with discrete spectral properties asshown in FIG. 88, so a band image having tissue information at a shallowlayer such as shown in “a” in FIG. 92 is captured in the image-pickupsignals taken by the CCD 402 with the B2 filter 414 b 2, a band imagehaving tissue information at the middle layer such as shown in “b” inFIG. 92 is captured in the image-pickup signals taken by the CCD 402with the G2 filter 414 g 2, and a band image having tissue informationat the deep layer such as shown in “c” in FIG. 92 is captured in theimage-pickup signals taken by the CCD 402 with the R2 filter 414 r 2.

As can be clearly understood from FIG. 87 and FIG. 88, at this time, thequantity of transmitted light from the second filter set is less thanthe quantity of transmitted light from the first filter set, since thebands thereof are narrowed, so the light adjusting circuit 443 controlsthe diaphragm device 413 by the light adjustment control parameterswitch-over circuit 444 outputting light adjustment control parametersaccording to the first filter set or second filter set of the rotatingfilter 414 to the light adjusting circuit 443, thereby, as shown in FIG.93, controlling the diaphragm device 413 when making narrow-band lightobservation so as to control light quantity Mx with a diaphragm controlcurve 462 corresponding to a set value Lx, as to, for example, a lineardiaphragm control line 461 by the diaphragm device 413 in normalobservation, corresponding to the set value Lx on an unshown settingpanel of the video processor 407.

Specifically, the aperture level value corresponding to the lightquantity setting value Lx changes from Mx1 to Mx2 as shown in FIG. 93,in a manner synchronous with changing the first filter set to the secondfilter set, and consequently, the diaphragm is controlled in thedirection of being opened, and acts to compensate for reduction in thequantity of illumination light by narrowing the bands of the filters.

The image processing circuit 430 of the present embodiment has aprocessing structure for calculating IHb (hemoglobin index) which is avalue correlated with the hemoglobin concentration in blood, using twoof the band image information from RGB, and specifically, as shown inFIG. 94, RGB signals input to the image processing circuit 430 aresubjected to inverse γ correction processing for removing the γcorrection performed for CRT display at the inverse γ correctionprocessing unit 461, with table conversion or the like.

Next, with regard to the GB signals subjected to inverse γ correction,signals to be sent to the subsequent processing are selected based oncontrol signals from the mode switch-over circuit 442 with the selectorunit 462. Next, following tone inversion processing at a tone inversionprocessing unit 463, multiplication with an R signal is performed at themultiplier 464. Finally, after being subjected to logarithmictransformation at a logarithmic transformation unit 465, output is madefrom the image processing circuit 430.

As for the output format from the image processing circuit 430, pseudocolor images may be generated based on the IHb, or one band image, e.g.,the R image may be substituted for the IHb image.

With conventional IHb, an expression of 32×Log 2 (R/G) is being used.This expression takes advantage of the fact that the G band imagereflects intensely blood information.

On the other hand, narrow-banding of the filter reflects intenselysurface capillaries to the B image. Accordingly, the B and G imagesfollowing filter switching differ in depth where the blood vesselsexist, so B reflects information of the surface layer, and G reflectslayer positions deeper than that.

Accordingly, with the present embodiment, upon the mode switch-overswitch 441 being pressed and the mode entering the narrow-bandobservation mode, the IHb value (32×Log 2 (R/B)) of the surface layer ofthe mucous membrane based on B information, and the IHb value (32×Log 2(R/G)) of the middle layer of the mucous membrane based on G informationcan be switched between and used by switching over the operations of theselector unit 462 shown in FIG. 94, so tissue information at a desireddepth near the tissue surface of the living body tissue can be separatedand visually recognized.

Now, while the operations of the selector unit 462 have been describedas being based on control signals from the mode switch-over circuit 442,a separate switch may be provided on the operating unit or the like ofthe electronic endoscope 403.

Next, a fourteenth embodiment of the present invention will be describedwith reference to FIG. 95 through FIG. 99.

FIG. 95 is a configuration diagram illustrating the configuration of anendoscope device, FIG. 96 is a configuration diagram illustrating theconfiguration of the image processing circuit shown in FIG. 95, FIG. 97is a configuration diagram illustrating the configuration of thefiltering execution unit shown in FIG. 96, FIG. 98 is a diagramillustrating the filter frequency properties of the filtering executionunit shown in FIG. 97, and FIG. 99 is a diagram illustrating RGB imagestaken when in the narrow-band observation mode in FIG. 95.

The fourteenth embodiment is almost the same as the thirteenthembodiment, so only the differing points will be described, and the sameconfigurations will be denoted with the same reference numerals anddescription thereof will be omitted.

The present embodiment relates to an endoscope which is capable ofswitching the spectral properties of illumination light to narrow-bandRGB properties, and which has, being interlocked therewith, functionsfor changing light quantity control parameters such as light adjustmenttables, and for changing image processing parameters.

As shown in FIG. 95, a processing switch-over instructing switch 470 isprovided for the electronic endoscope 403, and the image processingcircuit 430 receives control signals form the mode switch-over circuit442 and instruction signals from the processing switch-over instructingswitch 470, and performs the later-described color conversionprocessing.

Conventionally, spatial frequency filters such as FIR filters have beenused for image quality improvement and image enhancement processing inendoscopic image processing, and have been effective in assisting inobservation.

The image processing circuit 430 according to the present embodiment isof a configuration wherein this spatial frequency filtering is appliedto narrow-band RGB images, and as shown in FIG. 96, is configured of afiltering execution unit 471 for performing spatial frequency filteringprocessing with regard to input RGB images, a data converting unit 472for performing conversion of the output results of the filteringexecution unit 471 such as adjusting each of RGB to within an 8-bitlevel, and a coefficient converting unit 473 for changing the operationsof the filtering execution unit based on control signals from the filterswitch-over circuit 442 and instruction signals from the processingswitch-over instructing switch 470.

As shown in FIG. 97, the filtering execution unit 471 is made up offiltering units 481, 482, and 483, which perform 5×5 mask computationwith regard to each of the RGB image data, and adders 484, 485, and 486which perform weighting on the output of the filtering units 481, 482,and 483 and add to each of the RGB image data, wherein the coefficientchanging unit 473 sets mask coefficients to the filtering units 481,482, and 483 and weight coefficients to the adders 484, 485, and 486.

Accordingly, by performing computation such as shown in Expression 11,wherein the image data is represented by R(x, y), G(x, y), B(x, y), theoutput of the filtering units 481, 482, and 483 by Rs(x, y), Gs(x, y),Bs(x, y), and the weight coefficients by ωR, ωG, and ωB, spatialfrequency filtering processing results R′(x, y), G′(x, y), and B′(x, y)with the filter frequency properties such as shown in FIG. 98 forexample, are output.

Expression 11

R′(x,y)=R(x,y)+ωR·Rs(x,y) G′(x,y)=G(x,y)+ωG·Gs(x,y)B′(x,y)=B(x,y)+ωB·Bs(x,y)  (11)

The filter properties shown in FIG. 98 are properties which, whilesuppressing enhancement of noise components as much as possible in theorder of M1, M2, and M3, enhance the high-frequency components, and theenhanced bands are shifted to high frequencies in order. Such filterswith different enhanced bands are each individually applied torespective bands.

That is to say, as shown in FIG. 99, upon the mode switch-over switch441 being pressed to enter the narrow-band observation mode, the B imagehas smaller blood vessel patterns than the R image, i.e., higherfrequency properties, and M3 is applied rather than filter M1 in orderto reproduce these patterns more clearly. The R image is contrary, andapplication of M1 is more suitable than M3. Thus, it is important to usethe filter properties according to the contents of the body informationwhich the bands reproduce.

Also, such filter properties are effective for narrow-band RGB images,and separate filter properties are required for normal observation.Accordingly, the coefficient changing unit 473 changes the filterproperties to those which are optimal according to the mode switch-overcircuit 442. Control by instruction signals from the processingswitch-over instructing switch 470 performs adjustment of enhancementlevel and so forth, for example.

Thus, according to the present embodiment as well, tissue information ata desired depth near the tissue surface of the living body tissue can beseparated and visually recognized.

Next, a fifteenth embodiment of the present invention will be describedwith reference to FIG. 100 through FIG. 103.

FIG. 100 is a configuration diagram illustrating the configuration of animage processing circuit, FIG. 101 is a diagram illustrating a tonecorrection table in the pre-processing unit in FIG. 100, FIG. 102 is adiagram illustrating histogram distribution applied to edge extractingprocessing in the edge extracting processing unit shown in FIG. 100, andFIG. 103 is a diagram describing processing in the pattern extractingunit shown in FIG. 100.

The fifteenth embodiment is almost the same as the fourteenthembodiment, so only the differing points will be described, and the sameconfigurations will be denoted with the same reference numerals anddescription thereof will be omitted.

The present embodiment illustrates a configuration which changesparameters for extracting angiography patterns or extracting minutestructure patterns on mucous membrane surfaces in interlocking withfilter switching. Narrow-band RGB images are characterized in that theindependency of information represented between bands is high. Forexample, in the narrow-band observation mode wherein the modeswitch-over switch 441 is pressed, differential information is reflectedbetween bands, such as shown in FIG. 99, wherein the B image reflectsminute structure patterns on mucous membrane surfaces and blood vesselnetworks near the surface layer of mucous membranes, the G imagereflects blood vessel networks existing near the middle layers, and theR image reflects relatively thicker blood vessel networks existing atdeep layers of the mucous membranes, and each type of information isdeeply related with the change of the living body tissue in the depthdirection. With regard to such narrow-band RGB images, more effectiveresults can be expected by further optimizing the parameters rather thanapplying pattern extraction processing in normal observation.

Accordingly, as shown in FIG. 100, the image processing circuit 430according to the present embodiment comprises a band selector unit 491for selecting each of the RGB band image data, which selects a band toapply to the processing in the subsequent pattern extracting processingunit 492, which comprises pre-processing unit 493, edge extractingprocessing unit 494, and pattern extracting unit 495.

Here, one band or multiple bands may be used, and selection is madeaccording to extracted information. In the event that extraction ofpatterns of minute structures at the surface of mucous membranes isdesired, the B image is selected here. Or, in the event that theposition of thick blood vessels in layers of the mucous membranes isdesired, the R image is selected.

In the pattern extracting processing unit 492, pre-processing isperformed at the pre-processing unit 493. In general pre-processing,suitable pre-processing is performed according to subsequent processing,such as distortion correction, tone correction, and so forth. In theevent of performing processing such as for angiography patterns,distortion correction processing for correcting distortion aberration ofthe image-pickup optical system, and histogram smoothing processing forstandardizing concentration distribution is performed. For example, inthe case of tone correction, a tone correction table F such as shown inFIG. 101 is applied to band data f(x, y) input to the pre-processingunit 493, to obtain output g(x, y) (=F (f(x, y)). Note that in the tonecorrection table in FIG. 101, curve b converts to a stronger contrastthan curve a.

Next, in the edge extracting processing unit 494, edge extractionprocessing is performed. A method wherein a trough in a histogramdistribution is discovered and binarization processing is performed atthat level as shown in FIG. 102, or a method wherein edge extraction isperformed using a differential operator, can be used for this.

Next, at the pattern extracting unit 495, assuming the area of theregion A as M for example, as shown in FIG. 103, this M is compared witha predetermined threshold value θ, and in the event that M<θ, the regionA is removed as an unnecessary pattern, and only patterns having regionsof blood vessels and the like having area of θ or greater are extracted.Specifically, elimination and consolidation of patterns is performed byexpansion or reduction processing, or collation with reference patterns.

With the series of processing performed at the pattern extractingprocessing unit 492, parameters must be optimized for each piece ofinformation represented in each band. For example, in the patternextracting unit 495, in the event that extracting blood vessels runningat deep portions from the R image is desired, operations are made toeliminate fine independent points as much as possible, and in the eventof extracting capillary angiography patterns from the B image,operations are made to leave the fine patterns as much as possible.

The processing results of the pattern extracting processing unit 492 areoutput to a final stage image synthesizing unit 496, and at the imagesynthesizing unit 496, image synthesizing for reflecting the patternextracting results in the image is performed. Here, processing foradding the pattern extracting results to the original RGB image, orprocessing for configuring a monochromatic image from pattern extractionresults alone, is performed.

The operations of the above-described image processing circuit 430optimize the overall operations by the coefficient changing unit 473changing the coefficients of the processing units based on controlsignals from the mode switch-over circuit 442 and processing switch-overinstructing switch 470. With regard to the mode switch-over circuit 442,control is made so as to bypass pattern extracting processing in thecase of normal RGB illumination, and pattern extraction processing basedon control signals from the processing switch-over instructing switch470 is performed in the image processing circuit 430 in the event ofnarrow-band RGB illumination.

Thus, according to the present embodiment as well, tissue information ata desired depth near the tissue surface of the living body tissue can beseparated and visually recognized.

Embodiments of the present invention have thus been described, but it isneedless to say that the present invention is by no means restricted tothe above embodiments, and various modifications may be made within thespirit and scope of the present invention.

INDUSTRIAL APPLICABILITY

As described above, according to the present invention, firstly, anendoscope device and light source device capable of obtaining tissueinformation of a desired depth near the tissue surface of the livingbody tissue, can be provided.

Also, secondly, an endoscope device whereby tissue information of adesired depth near the tissue surface of the living body tissue can beseparated and visually recognized, can be provided.

1. An endoscope device, comprising: an illumination light supplyingsection for supplying illumination light including a visible lightregion; an endoscope having image-pickup section for irradiating theillumination light on a subject and picking up an image of the subjectby return light; a signal processing section for signal processingimage-pickup signals from the image-pickup section; and a bandrestricting section for restricting to narrow a band of at least one ofa plurality of wavelength regions of the illumination light andperforming image formation of a band image of a discrete spectraldistribution of the subject on the image-pickup section, the bandrestricting section being disposed to be arrangeable on an optical pathfrom the illumination light supplying section to the image-pickupsection, wherein the signal processing section performs spatialfrequency filtering processing for each of wavelength regions of theimage-pickup signals with the band of the at least one wavelength regionnarrowed by the band restricting section.
 2. The endoscope deviceaccording to claim 1, wherein the illumination light supplying unitcomprises a light quantity control unit for controlling the quantity oflight of the illumination light for each of the wavelength regions,according to restriction by the band restricting unit.